I have tried that. It doesnt work. 

Amethyst requires many image sizes, including the original size. Even without the original size, rescaling for all sizes the app can use takes more space than just keeping the original.  

 For profile pictures you do not need the original size usually.

Have a proper cache with mixed LRU/LFU and store 2 sizes: the original, and a smaller optimized version that can be on-demand scaled down to whatever you need. 

 It's funny that you think I don't have a proper cache even though I use state of the art caching system. 

 Also, scaling is not an issue since most Gif pictures are close to the size on the screen. The real culprit is the animation and the time of the gif. 

 can we just stop having GIFs and use APNG and/or normal video files