Continuing here instead of on itch.
Archive of old levels: https://web.archive.org/web/20110830033044/http://jumpnbump.spaceteddy.net/
The all levels zip still works there.
Tested porting a level and it works. I could probably script the conversion using Gimp. Never done that before but it would be interesting to explore the possibility. My end goal is to get all levels working in "Jump 'n Bump - remastered"