How to Run a Shopify Image Audit and Grade Your Store's Speed Performance

Most Shopify merchants know their store could be faster. Very few know exactly which pages are slow, which images are the cause, and what fixing each one is worth. A proper image audit answers all three questions — and for most stores, the answers are more impactful than any theme or code change.

What a Shopify Image Audit Covers

A thorough Shopify image audit examines every image on your store and assesses it against three criteria:

Format: Is it in the right format? PNG images used for photographs should be JPGs. GIFs should be static images or videos.

Dimensions: Is it the right size? Images larger than 2048px on their longest edge are sending unnecessary data to every visitor.

Compression: Is it compressed appropriately? JPG files saved at full quality from professional cameras or editing software are typically 4–10× larger than they need to be.

The output should be grouped by page (not just a flat list of files) so you can see which product pages have the worst performance and prioritise accordingly.

How to Run a Speed Audit on Your Shopify Store

Option 1: Google PageSpeed Insights. Free, no install required. Paste your URL and get a score. The limitation: it tests one page at a time, the image recommendations are generic, and you can’t easily act on them inside Shopify.

Option 2: GTmetrix or WebPageTest. More detailed than PageSpeed Insights but still single-page. Good for diagnosing specific pages, not for auditing your whole catalogue.

Option 3: A dedicated Shopify image audit tool. AssetScope’s Speed Audit scans your entire Files library and all product pages in about 30 seconds, grades each page A–F, and provides actionable per-image recommendations with estimated savings. Because it connects to your Shopify admin directly, it can also fix the issues it finds without leaving the app.

Understanding the A–F Speed Grade

AssetScope grades each product page on a 100-point scale based on the severity and number of image issues found. The grade letters map to:

A (90–100): Excellent. Images are well-optimised. Minimal opportunity for improvement.

B (75–89): Good. Minor issues. Worth fixing but not urgent.

C (60–74): Average. Noticeable image weight. Fixing these pages will produce a measurable speed improvement.

D (40–59): Poor. Significant image issues. These pages are materially slowing your store.

F (below 40): Critical. Severely unoptimised images. High priority for any store caring about conversions.

Pages graded D or F should be treated as urgent. The conversion impact of a 4–6 second mobile load time is severe.

Turning the Audit Into Action

An audit is only valuable if it drives action. For each image issue AssetScope identifies, it provides a one-click fix workflow: preview the optimised version, confirm the quality, and save it back to your Shopify Files library.

For images that need safe replacement (where the original is referenced in your theme), AssetScope scans your active theme’s Liquid files first to check for hardcoded URL references, then replaces the image with the optimised version.

See all 15 tools in AssetScope →