[Suicide Junkie]

I was referring to the modder who would be forced to examine each component in their mod, and see if the image it uses was moved.

What about subdividing the imagemod packs into themes, all being separate, small downloads?
The minis would be the "core" package, and there would be a host of portrait packages. Cubeworldpack, Hubblepack, CartoonPack, MiscPack etc.

That should reduce the download time, while leaving the images with the same numbers.