have you tried setting the img attribute "loading = 'lazy' " ? I haven't used it myself but perhaps it could help (?). See more here https://www.w3schools.com/tags/att_img_loading.asp

Alternatively, you could also try to reduce the size of your images. Not with HTML or css but the size of the original image file.

i need to know, too!!! but, i think it might be that my site images tend to be heavy :-(