Skip to main content

CMS Image Audit

The CMS image audit lives at /sites/[siteId]/cms-audit and is separate from PageSpeed scans. It walks your Webflow CMS collections directly via the Webflow API and flags every image field whose source file is oversized on dimensions, file size, or both.

Why it's separate from PageSpeed​

PageSpeed only tells you a page is slow. It can't tell you that collection item "2024 Annual Review" has a 6MB hero image — because that item may not be on any page PSI ran against. The CMS audit scans every collection item regardless of whether it's currently rendered.

Per-site thresholds​

Each site has its own limits. Set them once on the audit page:

SettingDefaultWhat it does
Max dimension2560pxFlag any image wider or taller than this.
Max file size500 KBFlag any image bigger than this.

Pick thresholds that match your site's actual needs. A product photography site should allow more than a blog.

What the audit gives you​

  • Per-collection rollup — collections with the most oversized items bubble to the top.
  • Item list — every oversized image with its dimensions, file size, collection, and the item slug.
  • Direct Editor link — each row links straight to the CMS item in Webflow's Editor, so you can swap the image without hunting for it.
  • CSV export — download the full list to hand to a VA or junior designer.

CSV columns​

collection,item_slug,item_name,field_name,image_url,width,height,file_size_bytes,webflow_editor_url
  1. Run the audit.
  2. Export to CSV.
  3. Batch-resize the worst offenders with your tool of choice — ImageOptim, Squoosh, TinyPNG, or sharp if you're scripting it.
  4. Re-upload via the Editor using the provided link per row.
  5. Re-run the audit to confirm.
Webflow auto-compresses on upload

Webflow will generate responsive variants from your uploaded asset, but it can't rescue a 12MP hero. Start with source assets sized to your layout.

Not covered: alt text

The CMS audit is about file size. Missing alt text shows up in the Accessibility Deep Dive. They're two different problems with two different scanners.

What's next​

After fixing oversized images, run a full scan — you'll usually see LCP improve immediately on pages that use those CMS items.