Free Image Optimisation Checker

What this image optimisation checker checks

This free image optimisation checker scans every image on the page you enter and flags two of the most common problems at once: oversized images larger than 100kb that slow your page down, and images missing alt text that hurt accessibility and image SEO. It reads each image's transfer size and its alt attribute so you get both performance and accessibility findings in a single scan.

For a deeper dive on writing alt text, read the alt text guide.

Why image weight matters

Images are usually the heaviest thing on a page, so an unoptimised hero or a gallery of full-resolution photos is often the single biggest drag on your Largest Contentful Paint. Every image over 100kb that could be a fraction of that size is wasted load time your visitors feel directly.

Alt text is the other half: it makes images understandable to screen readers and to search engines, unlocking Google Images traffic. One scan surfaces both the weight problem and the accessibility gap.

How to fix oversized and un-described images

Getting image weight down is usually the highest-impact performance fix you can make:

• Compress and resize: serve images at the dimensions they actually display at, and compress them. Most photos can drop well below 100kb with no visible quality loss.
• Use modern formats: WebP or AVIF are dramatically smaller than JPEG or PNG for the same quality.
• Lazy-load below-the-fold images so they do not compete with the hero for initial bandwidth.
• Add descriptive alt text to every meaningful image, and alt="" to purely decorative ones.

Honest limits

This tool checks up to 20 images on the single page you enter, reading each one's reported transfer size; a server that omits the size header may leave a few images unmeasured. To measure image weight against your actual LCP, pair it with the Core Web Vitals checker, and for a site-wide audit with AI fix instructions and a PDF report, run a full free audit.