Oversized images: what it is and how to fix it
What it is
Images are far larger than they need to be.
Why it matters to a client
Heavy images are the most common reason a page feels slow on a phone, and phone visitors are the ones most likely to leave.
How to find it
Check the page in PageSpeed Insights on mobile, or open the Performance tab of the site in AuditOpti — we pull the same Google data for the homepage and the top crawled pages.
How to fix it
Export images at the size they actually display, save them as WebP, and let the site load them lazily below the fold.
- 1Install an image optimization plugin and convert the library to WebP.
- 2Make sure the hero image is not lazy-loaded — lazy loading the largest visible image makes this metric worse, not better.
- 3Defer or remove render-blocking scripts loaded in the head, especially chat and heatmap widgets.
- 4Re-test in PageSpeed Insights on mobile, not desktop.
How AuditOpti prioritizes it
AuditOpti scores this as medium severity by default, then multiplies it by how many pages are affected — one page is not the same problem as a hundred. After that, the AI re-ranks it against everything else on the site by likely business impact, so a medium-severity problem on a service page can outrank a critical one on a page nobody visits.
Check a site for this
Run a free audit and we'll tell you whether this issue is present — along with everything else worth fixing.