PERF-004
Images are not compressed
MediumDefault severity · Performance · SEO, quality and performance
Last reviewed
What it checks
File size and format of up to 8 images on the page (HEAD requests): PNG, JPEG or GIF over 300 KB, or any image over 1 MB. WebP, AVIF and SVG under 1 MB are already efficient formats and are not reported.
Why it matters
Oversized images are the most common cause of slow pages and high mobile data use.
Recommended fix
Resize images to their display size and serve WebP or AVIF, with lazy loading below the fold.
How to verify
Reload with DevTools → Network filtered to images and confirm each is under 200 KB.
Example fix prompt
Generic prompt (your report adds the evidence)
Please fix this production issue in my app.
Issue PERF-004: Images are not compressed
Site: https://your-app.example
First confirm the issue in the code or live config. If it is not present, say so and change nothing.
Task: Optimize the images listed in the evidence: resize to the largest size they are displayed at, convert to WebP or AVIF, add width and height attributes, and lazy-load images below the fold (use the framework image component if available).
Constraints: make the smallest change that fixes this, keep the current design and behaviour, never paste secret values into code or chat, and tell me which files you changed.
Done when: Reload with DevTools → Network filtered to images and confirm each is under 200 KB.