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Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.
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Detailed Report

Audit breakdown by category with detailed findings.

35

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

Why this matters

Performance issues directly impact user engagement and conversion rates.

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

Why this matters

Performance issues directly impact user engagement and conversion rates.

RequestCache TTLTransfer Size
www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg0.0 ms194.0 KiB
/media/y23j50po/3-exhibition-listing-square-phase-1-600-x...604800.0 s1.2 MiB
www.nationalgallery.org.uk/css/base.bundle.css?v=FbvHCoIUzHVBsPoMGeAGUFy9OXU0.0 ms71.7 KiB
consent.cookiebot.com/Framework/IAB/consent-sdk-2.3.js493.0 s66.4 KiB
/media/xk0om41s/waldmüller-2026-_website_3-exhibition-li...604800.0 s505.0 KiB
www.nationalgallery.org.uk/css/partials.bundle.css?v=8uGWc-oclJU5MuONOykQYGBNSKQ0.0 ms46.1 KiB
/media/jc4pptxy/wod-exhibition-highlight-homepage-698-x-4...604800.0 s340.7 KiB
consent.cookiebot.com/uc.js1080.0 s27.0 KiB
/media/sq5pr14q/zurbaran_angle-cut-image-and-copy-block-8...604800.0 s236.1 KiB
/media/h4hcciro/renoir-and-love-exhibition-listing-square...604800.0 s228.6 KiB
www.nationalgallery.org.uk/js/partials.bundle.js?v=nhEE2wWm83K-TJMVyz3Yzk8BmAQ0.0 ms22.1 KiB
/media/29272/daily-guided-tour-people-in-the-national-gal...604800.0 s208.6 KiB
f.vimeocdn.com/p/4.46.43/js/player.module.js1209600.0 s211.3 KiB
/media/a4xgmnwe/061-hd-23022017-2663-life-drawing.jpg?wid...604800.0 s148.8 KiB
/media/wmfdretp/single-use-april-2026-alice-boyd.jpg?rxy=...604800.0 s137.2 KiB
/media/jqllhs4e/single-use-april-2026-steven-fowler.jpg?r...604800.0 s118.6 KiB
/media/ts0ponok/event_longfordestatesartwork_0095_1920px....604800.0 s112.9 KiB
/media/jk4fbnxa/vey_exhibition_crops-575-x-320-2.jpg?rmod...604800.0 s102.0 KiB
/media/xomftqiq/exhibition-listing-square-600-x-600.jpg?r...604800.0 s96.1 KiB
f.vimeocdn.com/p/4.46.43/js/vendor.module.js1209600.0 s93.5 KiB
player.vimeo.com/api/player.js1800.0 s8.9 KiB
/media/d5rfoyrb/n-3070-00-000102-fs-hd.jpg?cc=0.093757352...604800.0 s72.1 KiB
www.nationalgallery.org.uk/v2/img/logos/ng-logo-white-320.png0.0 ms7.2 KiB
/media/3wnbcxn3/friday_lates_life_drawing_1920x1080_optim...604800.0 s67.0 KiB
/media/xwbnkex3/children-drawing-at-family-event.jpg?cc=0...604800.0 s53.3 KiB
/media/29482/roller-printmaking-images-copy-creative-jr-m...604800.0 s51.3 KiB
/media/rgxdu1nk/n-6664-00-000023-xl-hd.jpg?rxy=0.51827956...604800.0 s39.9 KiB
/media/0gchqr4h/single_use_april_2026_chloe_aridjis_2_192...604800.0 s38.0 KiB
/v3/css/views/home-page.css?v=0hYt9XLfBLfWGnX4SW1WGv68Q3I0.0 ms3.8 KiB
/media/wqpe1kxe/n-0172-00-000104-xl-hd.jpg?rxy=0.50671834...604800.0 s37.8 KiB
f.vimeocdn.com/p/4.46.43/css/player.css1209600.0 s23.9 KiB
www.nationalgallery.org.uk/v2/img/logos/tiktok-circle.svg0.0 ms2.0 KiB
www.nationalgallery.org.uk/v2/img/logos/instagram-circle.svg0.0 ms1.8 KiB
www.nationalgallery.org.uk/v2/img/logos/threads-circle.svg0.0 ms1.8 KiB
/v2/css/umbraco-forms.css?v=hZ6S1nIk4YaYG17DLLQ3mbzc_Ds0.0 ms1.2 KiB
www.nationalgallery.org.uk/v2/img/logos/youtube-circle.svg0.0 ms1002 B
/v3/img/icons/black/mail-tilted.svg?v=gBfXtfDEHxBAw1C0win...0.0 ms984 B
www.nationalgallery.org.uk/v3/img/icons/white/search.svg0.0 ms973 B
www.nationalgallery.org.uk/v2/img/logos/facebook-circle.svg0.0 ms936 B
www.nationalgallery.org.uk/v3/img/icons/white/close.svg0.0 ms810 B
www.nationalgallery.org.uk/v3/img/icons/white/account.svg0.0 ms803 B
www.nationalgallery.org.uk/v2/img/icons/search-grey.svg0.0 ms793 B
/v3/js/views/home-page.js?v=ArRyN_Oa6L-L_rZh8r9ny5QrTZ00.0 ms793 B
www.nationalgallery.org.uk/v3/img/icons/white/hamburger-menu.svg0.0 ms662 B
www.nationalgallery.org.uk/v2/img/logos/x-circle.svg0.0 ms657 B
/v3/img/icons/black/pause-circle.svg?v=gBfXtfDEHxBAw1C0wi...0.0 ms643 B
/v3/img/icons/yellow/arrow-left.svg?v=fx_3CG4ldbseYg_Ihdq...0.0 ms638 B
/v3/img/icons/white/arrow-left.svg?v=gBfXtfDEHxBAw1C0winr...0.0 ms620 B
/v3/img/icons/yellow/arrow-right.svg?v=fx_3CG4ldbseYg_Ihd...0.0 ms594 B
/v2/img/icons/back-arrow.svg?v=oANKjKsOvnBtH2SWoGobDFmVsyU0.0 ms588 B
/v3/img/icons/black/arrow-left.svg?v=gBfXtfDEHxBAw1C0winr...0.0 ms586 B
/v3/img/icons/black/arrow-right.svg?v=gBfXtfDEHxBAw1C0win...0.0 ms580 B
/v3/img/icons/black/info.svg?v=gBfXtfDEHxBAw1C0winrvugNnP00.0 ms559 B
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg0.0 ms558 B
www.nationalgallery.org.uk/v2/img/icons/close-thin.svg0.0 ms432 B
/v3/img/icons/black/circle-filled.svg?v=gBfXtfDEHxBAw1C0w...0.0 ms250 B
/v3/img/icons/black/circle.svg?v=gBfXtfDEHxBAw1C0winrvugNnP00.0 ms231 B

Your first network request is the most important. Reduce its latency by avoiding redirects, ensuring a fast server response, and enabling text compression.

Why this matters

Performance issues directly impact user engagement and conversion rates.

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

Why this matters

Performance issues directly impact user engagement and conversion rates.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:28.826 source:map[column:39808 line:17 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:38.55 source:map[type:text value:[unattributed]]] map[reflowTime:1.164 source:map[column:110 line:7 type:source-location url:https://www.nationalgallery.org.uk/js/partials.bundle.js?v=nhEE2wWm83K-TJMVyz3Yzk8BmAQ urlProvider:network]] map[reflowTime:22.662 source:map[column:6693 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:0.593 source:map[column:57332 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:0.341 source:map[column:57392 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:0.313 source:map[column:57456 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:4.433 source:map[column:6715 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:0.484 source:map[column:58397 line:16 type:source-location url:https://www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg urlProvider:network]] map[reflowTime:0.376 source:map[column:162161 line:1 type:source-location url:https://consent.cookiebot.com/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&referer=www.nationalgallery.org.uk&dnt=false&init=false&framework=TCFv2.3 urlProvider:network]] map[reflowTime:10.832 source:map[column:208496 line:1 type:source-location url:https://consent.cookiebot.com/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&referer=www.nationalgallery.org.uk&dnt=false&init=false&framework=TCFv2.3 urlProvider:network]] map[reflowTime:3.753 source:map[column:218830 line:1 type:source-location url:https://consent.cookiebot.com/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&referer=www.nationalgallery.org.uk&dnt=false&init=false&framework=TCFv2.3 urlProvider:network]] map[reflowTime:0.606 source:map[column:111299 line:1 type:source-location url:https://consent.cookiebot.com/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&referer=www.nationalgallery.org.uk&dnt=false&init=false&framework=TCFv2.3 urlProvider:network]] map[reflowTime:0.479 source:map[column:112837 line:1 type:source-location url:https://consent.cookiebot.com/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&referer=www.nationalgallery.org.uk&dnt=false&init=false&framework=TCFv2.3 urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLResource SizeEst Savings
div.hero-banner > div.banner > picture > img#bannerImage div.hero-banner > div.banner > picture > img#bannerImage
/media/f1ib0cwv/animated-banner-sprin-still-_v2.png?width...334.0 KiB303.6 KiB
a.dl-product-link > div.thumbnail > div.thumbnail-inner > div.square-image a.dl-product-link > div.thumbnail > div.thumbnail-inner > div.square-image
/media/jc4pptxy/wod-exhibition-highlight-homepage-698-x-4...340.2 KiB236.1 KiB
body.modal-open > main.main > div.across-uk > div.image body.modal-open > main.main > div.across-uk > div.image
/media/yrhn0js2/across-the-uk_p7937-v5.jpg?width=1152&hei...155.0 KiB80.0 KiB
a.dl-product-link > div.thumbnail > div.thumbnail-inner > div a.dl-product-link > div.thumbnail > div.thumbnail-inner > div
/media/ts0ponok/event_longfordestatesartwork_0095_1920px....112.5 KiB47.4 KiB
li.card-item > div.card > a > img.card-img-top li.card-item > div.card > a > img.card-img-top
/media/5pvbe0dv/from-home-courses-n0654-563-x-352.jpg?wid...70.4 KiB46.0 KiB
div.carousel-object > div.item > div.image-container > img.image div.carousel-object > div.item > div.image-container > img.image
/media/tvcbd4xg/visit-carousel-must-see-paintings-1820-or...122.9 KiB38.3 KiB
li.card-item > div.card > a > img.card-img-top li.card-item > div.card > a > img.card-img-top
/media/ulxjveul/from-home-pom-april-n6569-563-x-352.jpg?w...34.3 KiB9.8 KiB
The National Gallery div.pw-row > div.col-12 > div.logo > img
www.nationalgallery.org.uk/v2/img/logos/ng-logo-white-320.png7.0 KiB4.4 KiB

Optimize LCP by making the LCP image discoverable from the HTML immediately, and avoiding lazy-loading

Why this matters

Performance issues directly impact user engagement and conversion rates.

lhId: page-0-IMG
nodeLabel: div.hero-banner > div.banner > picture > img#bannerImage
path: 1,HTML,1,BODY,8,MAIN,1,DIV,0,DIV,0,PICTURE,3,IMG
selector: div.hero-banner > div.banner > picture > img#bannerImage
snippet: <img class="image" id="bannerImage" src="https://www.nationalgallery.org.uk/media/f1ib0cwv/animated-banner-sprin-st…" alt="" loading="eager">

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

Why this matters

Performance issues directly impact user engagement and conversion rates.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer SizeDuration
www.nationalgallery.org.uk/css/partials.bundle.css?v=8uGWc-oclJU5MuONOykQYGBNSKQ46.1 KiB455 ms
/v3/css/views/home-page.css?v=0hYt9XLfBLfWGnX4SW1WGv68Q3I3.8 KiB
www.nationalgallery.org.uk/css/base.bundle.css?v=FbvHCoIUzHVBsPoMGeAGUFy9OXU71.7 KiB1.1 s
/css2?family=Roboto:wght@300;400;500;700&family=Cormorant...2.4 KiB786 ms
consent.cookiebot.com/uc.js27.0 KiB1.1 s

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Redirects introduce additional delays before the page can be loaded. Learn how to avoid page redirects.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 837 ms
URLTime Spent
nationalgallery.org.uk/837 ms
www.nationalgallery.org.uk/0.0 ms

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

TTI

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 460 ms 120.8 KiB
URLTransfer SizeEst Savings
www.nationalgallery.org.uk/css/base.bundle.css?v=FbvHCoIUzHVBsPoMGeAGUFy9OXU71.6 KiB67.3 KiB
www.nationalgallery.org.uk/css/partials.bundle.css?v=8uGWc-oclJU5MuONOykQYGBNSKQ46.0 KiB42.2 KiB
13.5 KiB11.3 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 1.4 s 529.4 KiB
URLTransfer SizeEst Savings
www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg193.7 KiB152.3 KiB
www.googletagmanager.com/gtag/js?id=G-QX7LS2HRVL&cx=c&gtm=4e64k1176.8 KiB71.0 KiB
www.googletagmanager.com/gtag/js?id=AW-11258700076&cx=c&gtm=4e64k1143.4 KiB65.7 KiB
www.googletagmanager.com/gtag/js?id=AW-955301225&cx=c&gtm=4e64k1137.0 KiB65.3 KiB
www.googletagmanager.com/gtag/js?id=AW-979994843&cx=c&gtm=4e64k1137.1 KiB64.4 KiB
www.googletagmanager.com/gtm.js?id=GTM-TW25HX156.6 KiB62.2 KiB
consent.cookiebot.com/Framework/IAB/consent-sdk-2.3.js66.1 KiB48.4 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTotal CPU TimeScript EvaluationScript Parse
www.nationalgallery.org.uk/1.0 s34 ms4.0 ms
/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&r...1.0 s430 ms175 ms
Unattributable806 ms16 ms0.0 ms
www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg572 ms360 ms72 ms
www.googletagmanager.com/gtm.js?id=GTM-TW25HX441 ms340 ms64 ms
www.googletagmanager.com/gtag/js?id=AW-955301225&cx=c&gtm=4e64k1327 ms277 ms46 ms
www.googletagmanager.com/gtag/js?id=G-QX7LS2HRVL&cx=c&gtm=4e64k1269 ms200 ms66 ms
www.googletagmanager.com/gtag/js?id=AW-11258700076&cx=c&gtm=4e64k1261 ms210 ms49 ms
www.googletagmanager.com/gtag/js?id=AW-979994843&cx=c&gtm=4e64k1224 ms176 ms46 ms
consent.cookiebot.com/uc.js208 ms164 ms14 ms
consent.cookiebot.com/Framework/IAB/consent-sdk-2.3.js101 ms58 ms42 ms
www.nationalgallery.org.uk/js/partials.bundle.js?v=nhEE2wWm83K-TJMVyz3Yzk8BmAQ100 ms43 ms16 ms

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

Why this matters

Performance issues directly impact user engagement and conversion rates.

CategoryTime Spent
Script Evaluation2.4 s
Other1.2 s
Style & Layout689 ms
Script Parsing & Compilation598 ms
Parse HTML & CSS450 ms
Rendering170 ms
Garbage Collection30 ms

Many navigations are performed by going back to a previous page, or forwards again. The back/forward cache (bfcache) can speed up these return navigations. Learn more about the bfcache

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failure reasonFailure type
The page has an unload handler in a sub frame.Actionable

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URLTransfer Size
/1776901902-0xeebadbe8240fc437306248e05af350f043a656a5/2a...2.6 MiB
/media/y23j50po/3-exhibition-listing-square-phase-1-600-x...1.2 MiB
/media/xk0om41s/waldmüller-2026-_website_3-exhibition-li...505.0 KiB
/1776901902-0xeebadbe8240fc437306248e05af350f043a656a5/2a...476.7 KiB
/media/jc4pptxy/wod-exhibition-highlight-homepage-698-x-4...340.7 KiB
/media/f1ib0cwv/animated-banner-sprin-still-_v2.png?width...334.4 KiB
/7b3c581a-47fb-447f-ae48-1d195d909df2/cc.js?renew=false&r...295.0 KiB
/media/sq5pr14q/zurbaran_angle-cut-image-and-copy-block-8...236.1 KiB
/media/h4hcciro/renoir-and-love-exhibition-listing-square...228.6 KiB
f.vimeocdn.com/p/4.46.43/js/player.module.js211.3 KiB

Set an explicit width and height on image elements to reduce layout shifts and improve CLS. Learn how to set image dimensions

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
div.hero-banner > div.banner > picture > img#bannerImage div.hero-banner > div.banner > picture > img#bannerImage
/media/f1ib0cwv/animated-banner-sprin-still-_v2.png?width...
The National Gallery logo div.pw-container > div.logo > a > img
www.nationalgallery.org.uk/v2/img/logos/ng-logo-white-320.png
The National Gallery div.pw-row > div.col-12 > div.logo > img
www.nationalgallery.org.uk/v2/img/logos/ng-logo-white-320.png
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Audience div.panel-content > div > div.audience > img
www.nationalgallery.org.uk/v3/img/icons/grey/account.svg
Search form > div.text-and-button > button#TopBarSearchButton2 > img
www.nationalgallery.org.uk/v2/img/icons/search-grey.svg

More information about the performance of your application. These numbers don't directly affect the Performance score.

●Layout shift culprits
●Optimize DOM size
●Font display
●LCP breakdown
●Modern HTTP
●Optimize viewport for mobile
●Minify CSS
●Minify JavaScript
●User Timing marks and measures 5 user timings
●Avoid long main-thread tasks 17 long tasks found
●Network Requests
●Network Round Trip Times 20 ms
●Server Backend Latencies 250 ms
●Tasks
●Diagnostics
●Metrics
●Screenshot Thumbnails
●Final Screenshot
●Script Treemap Data
●Resources Summary
●Initial server response time was short Root document took 460 ms
●Avoid large layout shifts 1 layout shift found
○INP breakdown
○Avoid non-composited animations
97

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Until 31 May 2026 article.ng-card > a.dl-product-link > div.panel-content > div.date
Free article.ng-card > a.dl-product-link > div.panel-content > div.cost
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Zurbarán a.dl-product-link > div.panel-content > div.title > h3
2 May ‒ 23 August 2026 article.ng-card > a.dl-product-link > div.panel-content > div.date
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Waldmüller: Landscapes a.dl-product-link > div.panel-content > div.title > h3
2 July – 20 September 2026 article.ng-card > a.dl-product-link > div.panel-content > div.date
Free article.ng-card > a.dl-product-link > div.panel-content > div.cost
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Renoir and Love a.dl-product-link > div.panel-content > div.title > h3
3 October 2026 – 31 January 2027 article.ng-card > a.dl-product-link > div.panel-content > div.date
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Van Eyck: The Portraits a.dl-product-link > div.panel-content > div.title > h3
21 November 2026 – 11 April 2027 article.ng-card > a.dl-product-link > div.panel-content > div.date
EXHIBITION article.ng-card > a.dl-product-link > div.panel-content > div.tag
Catharina van Hemessen: Signature Works a.dl-product-link > div.panel-content > div.title > h3
4 March – 30 May 2027 article.ng-card > a.dl-product-link > div.panel-content > div.date
Free article.ng-card > a.dl-product-link > div.panel-content > div.cost
Fully booked article.ng-card > a.dl-product-link > div.thumbnail > div.status
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
TOUR a.dl-product-link > div.panel-content > div > div.category
Guided tours of Longford Castle div.panel-content > div > div.title > h3.trimmed
Various dates from 23 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
TOUR a.dl-product-link > div.panel-content > div > div.category
Guided tour div.panel-content > div > div.title > h3.trimmed
Tuesdays, Wednesdays, Thursdays (excluding public holidays) a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
FESTIVAL a.dl-product-link > div.panel-content > div > div.category
Friday Lates div.panel-content > div > div.title > h3.trimmed
Fridays a.dl-product-link > div.panel-content > div > div.date
FOR HOUSE AND EXHIBITION MEMBERS a.dl-product-link > div.panel-content > div > div.audience
PERFORMANCE a.dl-product-link > div.panel-content > div > div.category
A literary salon: Chiaroscuro: A poetic interpretation of light and dark div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
COURSES | ART MAKING a.dl-product-link > div.panel-content > div > div.category
Leaves and layering: Botanical gelli printmaking div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
WORKSHOP a.dl-product-link > div.panel-content > div > div.category
Friday Lates life drawing: Originary Arts div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
MUSIC AND PERFORMANCE a.dl-product-link > div.panel-content > div > div.category
Friday Lates music: Alice Boyd and Rachel Kitchlew div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
MUSIC AND PERFORMANCE a.dl-product-link > div.panel-content > div > div.category
Friday Lates: Stilled shadows: A magic lantern show with Chloe Aridjis div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR EVERYONE a.dl-product-link > div.panel-content > div > div.audience
TALKS AND CONVERSATIONS a.dl-product-link > div.panel-content > div > div.category
Friday Lates tour and poetry readings: SJ Fowler and guests div.panel-content > div > div.title > h3.trimmed
Friday, 24 April 2026 a.dl-product-link > div.panel-content > div > div.date
FOR FAMILIES - ALL AGES a.dl-product-link > div.panel-content > div > div.audience
WORKSHOP a.dl-product-link > div.panel-content > div > div.category
The Roden Centre for Creative Learning: The Welcome space, our dedicated space … div.panel-content > div > div.title > h3.trimmed
Saturday and Sundays, Bank holidays and school holidays (Westminster Borough) a.dl-product-link > div.panel-content > div > div.date
FOR SCHOOLS & TEACHERS a.dl-product-link > div.panel-content > div > div.audience
COURSES | STUDY DAY a.dl-product-link > div.panel-content > div > div.category
Online Take One Picture CPD: 2025-2026 div.panel-content > div > div.title > h3.trimmed
Various dates from 27 April 2026 a.dl-product-link > div.panel-content > div > div.date
LEARNING div.card > a > div.card-body > p.tags
Courses div.card > a > div.card-body > h3.card-title
Join our global community to discover a world of art div.card > a > div.card-body > p.sub-text

These are opportunities to improve the legibility of your content.

○Interactive controls are keyboard focusable
○Interactive elements indicate their purpose and state
○The page has a logical tab order
○Visual order on the page follows DOM order
○User focus is not accidentally trapped in a region
○The user's focus is directed to new content added to the page
○HTML5 landmark elements are used to improve navigation
○Offscreen content is hidden from assistive technology
○Custom controls have associated labels
○Custom controls have ARIA roles
●`[aria-*]` attributes match their roles
●`[aria-hidden="true"]` is not present on the document `<body>`
●`[role]`s have all required `[aria-*]` attributes
●`[role]` values are valid
●`[aria-*]` attributes have valid values
●`[aria-*]` attributes are valid and not misspelled
●Buttons have an accessible name
●Image elements have `[alt]` attributes
●`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
●ARIA attributes are used as specified for the element's role
●Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
●`[aria-hidden="true"]` elements do not contain focusable descendents
●Elements use only permitted ARIA attributes
●Document has a `<title>` element
●`<frame>` or `<iframe>` elements have a title
●`<html>` element has a `[lang]` attribute
●`<html>` element has a valid value for its `[lang]` attribute
●Links are distinguishable without relying on color.
●Links have a discernible name
●Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
●List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
●No element has a `[tabindex]` value greater than 0
●Touch targets have sufficient size and spacing.
●`[lang]` attributes have a valid value
●Heading elements appear in a sequentially-descending order
●Document has a main landmark.
●Deprecated ARIA roles were not used
○`[accesskey]` values are unique
○`button`, `link`, and `menuitem` elements have accessible names
○ARIA input fields have accessible names
○ARIA `meter` elements have accessible names
○ARIA `progressbar` elements have accessible names
○Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
○`[role]`s are contained by their required parent element
○Elements with the `role=text` attribute do not have focusable descendents.
○ARIA toggle fields have accessible names
○ARIA `tooltip` elements have accessible names
○ARIA `treeitem` elements have accessible names
○The page contains a heading, skip link, or landmark region
○`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
○Definition list items are wrapped in `<dl>` elements
○ARIA IDs are unique
○No form fields have multiple labels
○`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
○Input buttons have discernible text.
○`<input type="image">` elements have `[alt]` text
○Form elements have associated labels
○The document does not use `<meta http-equiv="refresh">`
○`<object>` elements have alternate text
○Select elements have associated label elements.
○Skip links are focusable.
○Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
○`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
○`<video>` elements contain a `<track>` element with `[kind="captions"]`
○Tables have different content in the summary attribute and `<caption>`.
○All heading elements contain content.
○Uses ARIA roles only on compatible elements
○Image elements do not have `[alt]` attributes that are redundant text.
○Identical links have the same purpose.
○Elements with visible text labels have matching accessible names.
○Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
○`<td>` elements in a large `<table>` have one or more table headers.
100

Best Practices

General

Source maps translate minified code to the original source code. This helps developers debug in production. In addition, Lighthouse is able to provide further insights. Consider deploying source maps to take advantage of these benefits. Learn more about source maps.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL
www.nationalgallery.org.uk/js/base.bundle.js?v=Dp7nD6RiZXslvTCzPBEm3D0fQQg
●Uses HTTPS
●Avoids deprecated APIs
●Avoids third-party cookies
●Allows users to paste into input fields
●Avoids requesting the geolocation permission on page load
●Avoids requesting the notification permission on page load
●Displays images with correct aspect ratio
●Serves images with appropriate resolution
●Page has the HTML doctype
●Properly defines charset
●No browser errors logged to the console
●No issues in the `Issues` panel in Chrome Devtools
●Ensure CSP is effective against XSS attacks
●Use a strong HSTS policy
●Ensure proper origin isolation with COOP
●Mitigate DOM-based XSS with Trusted Types
●Detected JavaScript libraries
○Redirects HTTP traffic to HTTPS
○Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

○Structured data is valid
●Page isn’t blocked from indexing
●Document has a `<title>` element
●Document has a meta description
●Page has successful HTTP status code
●Links have descriptive text
●Links are crawlable
●robots.txt is valid
●Image elements have `[alt]` attributes
●Document has a valid `hreflang`
●Document has a valid `rel=canonical`

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