Images Optimization

Using WordPress as a marketplace or service website is really not easy especially if you are adding a lot of images. Due to unused images and the thousands of extra generated copies which usually add extra load on DB and host.

So what is the best option get optimized load speed with low background operation which really put huge load on my server.(3 websites hosted there)

I tried changing all sizes to 0 and prevent image generation but it made issue in thumbnails in media library and in the website.
used plugins to force generate images but still don’t solve a problem

Eventually i want to make 1 folder where i add the images for the 3 websites together but that doesn’t read the files automatically from folders and must add them through a plugin which mess the DB even more.

I need a good solution to reduce files numbers and don’t cause broken thumbnails in media library or the interface