Some time ago I made a dedicated page about the art of C64-Disc-Covers and scanned my (rather small) collection.

Back in the 80s and 90s all C64-Scene-Releases like new Demos, Discmags and Musicdiscs where mostly spread per Mail. There were a few BBSes around, but for most of the C64 sceners that whole thing was way too hot since you had to get into Blueboxing, Phreaking and Calling Card Hacking and the possible sentence if caught and sent to a court was not very amusing for most people and so BBS-Systems where mostly run and called by people who were more on the illegal side anyway (Crackers).
Every legal scener had some contacts that he swapped discs per mail with, in my best times I had about 40 people from all over europe that sent me packages with discs and I send them my packages with discs. Also those dics where 5 1/4″ floppy discs, in case you don’t remember (or never knew).

Now I have no idea who came up with the idea of disccovers, but it was like this : Some artist drew the outlines of a floppydisc paperbag on a A4-sheet of paper, made some art (mostly about a specific group, demo or discmag) and then just ran that paper over a xerox machine and send it to all his contacts, together with the disc that cover was made for. His contacts now got one copy, ran this copy over a xerox themselves and sent that copy to their other contacts and so forth.

Because everything mainly reduces to black and white if being copied a few times a unique style was born.

The page can be found here: http://www.loozabeats.de/c64covers/