If you want a fast site, fix your images. Rename files to be descriptive...

https://milossmartnews.bearsfanteamshop.com/what-is-schema-markup-for-images-and-does-it-help

If you want a fast site, fix your images. Rename files to be descriptive instead of using generic tags like "IMG_001." Write alt text that actually helps users and search engines understand the context