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https://irfanview.com

Performance

· 14 checks — Lighthouse + waterfall + sustainability rolled into one auditable list.
SCORE
91
GRADE
A
FIX
2
REVIEW
2
PASS
9
INFO
1

Performance-focused optimization plan with CWV assessment, top offenders, and time estimates

Mobile Desktop
98
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
61
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
100
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

787 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

907 ms

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

0 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.000

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

787 ms

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

907 ms

Page Load Progression

375 ms
750 ms
1.1 s
1.5 s
1.9 s
2.2 s
2.6 s
3.0 s
Checks
14
9 PASS 2 REVIEW 2 FIX
D
Third-Party Impact
Action
100% third-party, 0 ms blocking
FIX
100% third-party, 0 ms blocking
Warning::
Third-party code accounts for 100% of page weight (175.7 KiB of 175.8 KiB)
Info::
Third-party blocking time is low (0 ms)
100%
First-party Third-party
F
HTTP Caching
Action
No cache headers
FIX
No cache headers
Warning::
No Cache-Control header found
Browsers will use heuristic caching, which can be unpredictable. Set explicit cache headers.

No Cache-Control header

Adding a Cache-Control header can significantly improve repeat-visit performance.

C
Image Optimization
Action
12 images, 0 KB saveable
REVIEW
12 images, 0 KB saveable
Warning::
https://www.irfanview.com/images/logo.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.irfanview.com/images/banner_daisy.jpg is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.irfanview.com/images/profile-pic.gif is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.irfanview.com/images/logo-download.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
Warning::
https://www.irfanview.com/images/logo-footer.png is missing width/height — may cause layout shift
Set explicit width and height to prevent CLS.
12 images 164 KB
0 oversized -0 KB
12 legacy format
5 missing dimensions CLS risk

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

Set explicit width and height to prevent CLS.

Why this matters

Image without explicit width/height — browser can't reserve space; CLS jumps when image loads.

Source: web.dev / Core Web Vitals

C
Green Hosting
Action
Whether the site is served from green-energy infrastructure
REVIEW

Green Hosting

No green hosting detected

A+
Page Weight Budget
176 KB transferred, 16 requests
PASS
176 KB transferred, 16 requests
Info::
Page weighs 220 KB (176 KB transferred)
Info::
16 HTTP requests
Info::
Estimated 0.04 g CO2 per page load
176 KB / 2.4 MB budget
176 KB transferred
16 requests
0.04 g CO2 per page load
Images 163.7 KiB 93%
CSS 6.7 KiB 4%
Other 2.9 KiB 2%
HTML 2.5 KiB 1%
0 2.4 MB 4.9 MB
Under budget
A+
Text Compression
All text resources are compressed
PASS
All text resources are compressed
Info::
All text resources are compressed
All text resources are properly compressed.
A+
JS Execution Cost
No JS execution data
PASS
No JS execution data
Info::
No significant JS execution detected

Main Thread Breakdown

Style & Layout 44% Other 43% Rendering 6% Script Evaluation 4%
A+
Font Loading
No web fonts (system fonts)
PASS
No web fonts (system fonts)
Info::
No web fonts loaded — system fonts are fastest
No web fonts loaded — system fonts are optimal.
A+
JS Bundles
No JavaScript
PASS
No JavaScript
Info::
No JavaScript bundles
No JavaScript files loaded.
A+
Resource Caching
All resources properly cached
PASS
All resources properly cached
Info::
No caching issues found
All static resources have appropriate caching headers.
A+
Critical Rendering Path
No render-blocking resources
PASS
No render-blocking resources
Info::
No render-blocking resources detected
A+
Resource Hints
No optimization needed
PASS
No optimization needed
Info::
No resource hint issues
A
Page Weight Inventory
16 resources · 176 KB · 0 KB savings available
PASS
16 resources · 176 KB · 0 KB savings available
Info::
Within 1MB page-weight target
Got: 176 KB
Warning::
15 third-party resources (100% of weight)
16 resources · 175.8 KiB · 15 third-party Within 1MB page-weight target
Image 95% · 166.6 KiB
CSS 4% · 6.7 KiB
Document 1% · 2.5 KiB
Network Waterfall
16 requests over 783ms
INFO
0 ms 200 ms 400 ms 600 ms 800 ms FCP 787 ms LCP 907 mshttps://irfanview.com// https://irfanview.com/ — 301 — 99 B — 271 ms — h2https://www.irfanview.com/www.irfanview.com/ https://www.irfanview.com/ — 200 — 2.5 KiB — 104 ms — h2https://www.irfanview.com/style.csswww.irfanview.com/style.css https://www.irfanview.com/style.css — 200 — 6.7 KiB — 183 ms — h2https://www.irfanview.com/images/logo.pngwww.irfanview.com/images/logo.png https://www.irfanview.com/images/logo.png — 200 — 6.3 KiB — 178 ms — h2https://www.irfanview.com/images/banner_daisy.jpgwww.irfanview.com/images/banner_dai... https://www.irfanview.com/images/banner_daisy.jpg — 200 — 90.2 KiB — 176 ms — h2https://www.irfanview.com/images/profile-pic.gifwww.irfanview.com/images/profile-pi... https://www.irfanview.com/images/profile-pic.gif — 200 — 3.8 KiB — 176 ms — h2https://www.irfanview.com/images/logo-download.pngwww.irfanview.com/images/logo-downl... https://www.irfanview.com/images/logo-download.png — 200 — 6.2 KiB — 176 ms — h2https://www.irfanview.com/images/logo-footer.pngwww.irfanview.com/images/logo-foote... https://www.irfanview.com/images/logo-footer.png — 200 — 5.2 KiB — 176 ms — h2https://www.irfanview.com/images/icons.pngwww.irfanview.com/images/icons.png https://www.irfanview.com/images/icons.png — 200 — 3.2 KiB — 95 ms — h2https://www.irfanview.com/images/main-menu-bg.pngwww.irfanview.com/images/main-menu-... https://www.irfanview.com/images/main-menu-bg.png — 200 — 4.4 KiB — 92 ms — h2https://www.irfanview.com/images/banner-bg.jpgwww.irfanview.com/images/banner-bg.... https://www.irfanview.com/images/banner-bg.jpg — 200 — 35.7 KiB — 95 ms — h2https://www.irfanview.com/images/bullet2.pngwww.irfanview.com/images/bullet2.pn... https://www.irfanview.com/images/bullet2.png — 200 — 1.1 KiB — 97 ms — h2https://www.irfanview.com/images/download-icon-white.pngwww.irfanview.com/images/download-i... https://www.irfanview.com/images/download-icon-white.png — 200 — 1.4 KiB — 95 ms — h2https://www.irfanview.com/images/download-icon-black.pngwww.irfanview.com/images/download-i... https://www.irfanview.com/images/download-icon-black.png — 200 — 1.5 KiB — 97 ms — h2https://www.irfanview.com/images/features.pngwww.irfanview.com/images/features.p... https://www.irfanview.com/images/features.png — 200 — 4.7 KiB — 94 ms — h2https://www.irfanview.com/images/favicon.pngwww.irfanview.com/images/favicon.pn... https://www.irfanview.com/images/favicon.png — 200 — 2.8 KiB — 92 ms — h2
HTML JavaScript CSS Images Fonts XHR/Fetch Other
All checks on this page are automated. Results are estimates - run targeted manual reviews when the score affects a release decision.

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