Google mod_pagespeed for Apache/nginx does a good job of compressing images, it does things like use a 4:2:0 YUV colourspace and it also serves webp format to c

Google mod_pagespeed for Apache/nginx does a good job of compressing images, it does things like use a 4:2:0 YUV colourspace and it also serves webp format to clients that support such things. The advantage of the mod_pagespeed approach is that you can keep hi-res images in your web page and not have to be concerned with manually compressing things.