A Related Tangent is how FB handles different photo requests by saving 4 copies with different resolutions at the time of upload. It's even worse because according to [1]:
" The number of Haystack photos written is 12 times the number of photos uploaded since the application scales each image to 4 sizes and saves each size in 3 different locations. "
Keep in mind that the referenced paper that this page is based on is over a decade old now. Many things have changed since then, as you can imagine. Look for later papers and engineering blog posts for more about what’s changed since then.
