You do not need to reupload the image mod files. Just point people to:
http://imagemodserver.mine.nu/other/MM/SE4/imagemod/
or here while imagemodserver is offline:
http://imagemod.spaceempires.net/
If you have a handful of extra images, you can just submit them to the image mod and save people from downloading everything twice.
This will cut a lot of download size out of the mod...