Before you kids had your new-fangled see-dees and em-pee-threes, music was put onto cassette tapes. These are cards used to make your tape case look extra pretty.
Majority of these are just stills from the anime, repurposed manga art, or reused promotional material. I want to believe that some of these are original, but I have nothing to back that up.
123-140 come from different issues of the UY Shonen Sunday Graphics. Those will be posted... eventually. Horus didn't scan the entirety of those so it'll just be an incomplete gallery until someone else scans and uploads the full versions.
Don't know what 141 is about. It was in the folder so I included it.

Taken from Horus Urusei Eye, a website that was dedicated to hosting Urusei Yatsura official art but has been offline for quite some time now. The site also hosted a bunch of other things such as art of other Rumiko Takahashi works, TV show theme songs, and the host's own weird fetish edits. These have not been preserved as well as the UY aspect of the site, so they may as well be lost to time.
If anyone has a larger backup of Horus Urusei Eye or has found it under another domain, please PM me!