A Shopify store owner using the Craft theme is experiencing performance issues and poor Cumulative Layout Shift (CLS) scores caused by collection tile images, despite the images being properly sized. The images were optimized for mobile users but negatively impacted site performance.
Initial Problem:
Collection images (1600x1600) with srcset and sizes attributes were causing performance degradation
Tests confirmed images were properly sized, but CLS issues persisted
Various optimization attempts (smaller sizes, JPG format, 800x800 dimensions) didn’t resolve the issue
Solution Implemented:
Another user suggested editing the main-collection-banner.liquid file by removing the srcset and sizes attributes from the image tags, leaving only the basic src attribute with a fixed width of 750px.
Outcome:
Performance score improved by 20 points (reaching 67)
The store owner confirmed the fix worked after implementing the code changes
Remaining Issue:
The user now has a secondary concern about managing hover effects versus static display, but hasn’t received a response yet on this new question.
Summarized with AI on October 29.
AI used: claude-sonnet-4-5-20250929.
I have created collection tile images mainly for mobile users, but after I loaded them, my website performance took a hit, and they seem to be giving me poor cls. I ran the test, and it came back with properly sized images.
example:
How do I fix this? I have loaded smaller images, I have loaded jpg, instead of png, I have loaded 800x800 and I still get this.
Any other suggestions? I really like having the collection tile images… I think it helps via when using the mobile version but maybe I need to remove them and just use text squares.
I’m not sure what you mean by “content of this file”. www.created4ucreations.com if you go via mobile device you will see my collection images. It is those images that seems to be the issue.
My performance bumped up to a 67… so I gained 20 points in the right direction! Thank you!! Now I have one more issue… that maybe you know the work around too. I have looked to see how to maybe changed it from hoover default to static but I don’t see it.
But first - let me say thank you for your help. Sorry for the delay, I had grandchildren for past week and half, and working on my website had to take a back seat.