PageSpeedInsight and image gallery


Image gallery would be for me a fantastic tool. Pb: PSI don’t like it.
For example, the page below is rated 72 without image gallery and gets a poor 39 with 3 image galleries on it.
PSI gives me a suggestion to solve the pb : adding Preload key requests.

I am not sure how to use it.
Do you think it could work? Do you know where & which code I should add?

Would you explain in what way Pagespeed Insights doesn’t like the gallery?

The same page receive a score > 70/100 without image gallery and < 50 with the 3 images galleries.

Do you use the SEO assistant? It explains the issue.

The problem is not the gallery per se, rather it’s the animation above the fold that’s detected incorrectly, which becomes a major blow in terms of load completion time and layout shift.

The SEO assistant points this issue out, along with many others.

I made several atempts and you are probably right for the gallery, but I can’t find de cause of the pb.
The SEO assistant only points the missing images descriptions on the page, the absence of WebP and the absence of a 320px configuration. Nothing about the animation above the fold that’s detected incorrectly.