The image audit finds every image on a site and reports what’s wrong with it: files far bigger than they need to be, missing or useless alt text, formats that cost load time, and images loading in an order that slows the page a visitor is looking at.
Built in-house. It is my own tooling rather than a reseller’s dashboard, which is why it checks the things I act on rather than everything a generic tool can measure.
What it does
Images are usually the largest thing on a page and the least maintained. The audit measures them, ranks them by what they’re actually costing, and separates the two problems people tend to merge: images that slow the site down, and images that give search engines and screen readers nothing to work with.
Those need different fixes, and on most sites only one of them is urgent.
What it checks
| Check | What it looks at |
|---|---|
| File size | Weight per image, and the worst offenders by page |
| Dimensions | Whether images are far larger than the space they’re displayed in |
| Format | Whether modern formats are being used, and where they’d help most |
| Alt text | Missing, empty, duplicated, or filled with a file name |
| Loading | Whether below-the-fold images are lazy loaded and above-the-fold ones aren’t |
| Responsive sources | Whether different sizes are served to different screens |
| Layout shift | Whether width and height are set, so the page doesn’t jump as images load |
| Filenames | Whether they describe the image, and whether any contain characters that break links |
The order to fix them in
Not by count. A site with 800 images missing alt text and six enormous hero images should fix the six first, because they’re what a visitor waits for.
Alt text still matters, and on image-led sites it matters a lot, because the pictures carry the proposition and search engines get nothing from them without it. On one concept project I reviewed a fishery site with 128 images and no alt text at all, on a site where the photography was the strongest thing it had. But it’s a content job that can run steadily, where the file size work is a one-off with an immediate effect.
A detail that breaks things quietly
Image filenames containing brackets break markdown image syntax, which matters wherever content is written or migrated in markdown. It’s the kind of fault that survives a migration and only shows up as a missing image on a handful of pages, so it’s worth catching in the audit rather than after launch.
Example output
PAGE: /collections/lashes/ HERO: 1.4MB JPEG, displayed at 720px wide, served at 2400px. Converting and resizing saves about 1.1MB. BELOW FOLD: 22 product images, none lazy loaded. ALT TEXT: 18 of 22 missing. LAYOUT: No width or height set, so the grid jumps as images load. FIRST FIX: The hero, then lazy loading. Alt text as a content task.
What I review
Recommendations get checked against how the page actually renders, since a lazy loading rule applied to a hero image makes a page feel slower rather than faster. Where a site runs on a platform that resizes images automatically, the audit checks what’s actually being served rather than what’s been uploaded.
Limitations
- Compression is a judgement. There’s a point where a smaller file looks worse, and for product or jewellery photography that point arrives early.
- Alt text needs a person. It can be flagged automatically and shouldn’t be written automatically, because a description of the wrong thing is worse than none.
- Platform limits apply. Some systems restrict which formats and sizes can be served.
Services it powers
The image audit powers image SEO and feeds site speed and Core Web Vitals work. See the rest of the tools on the tech stack page.
FAQ
Do images really affect SEO?
They affect how quickly a page loads and how stable it is while loading, both of which are measured and both of which affect visitors. Alt text also gives search engines and screen readers the only description they get of what an image shows.
Should every image have alt text?
Every image that carries meaning should. Purely decorative images can have an empty alt attribute, which tells screen readers to skip them. Filling an alt attribute with a file name or a keyword list is worse than leaving it empty, because it describes nothing.
What’s the quickest image win on most sites?
Resizing and compressing the largest images on the pages people actually land on, usually the hero. On most sites a handful of files account for most of the weight, so fixing a few of them does more than working through hundreds of small ones.
See the whole toolkit
The tech stack page lists every tool, and the free assessment includes an image check.