Hey everters !
A few months ago, a friend "shrubbyfrog" and I went about researching Eversion's graphics and how they all work. We've figured most things out such as how sprites are constructed in different files, but are still a little stumped on some other things (like the whole extent of what each variable in the file headers do). Since we know how the sprite data itself works, they can be reconstructed and exported or "ripped". This program should work for all versions of the game, freeware and HD, and even works on some other Shiny engine games. I don't know if we'll make sure it works for any Shiny engine game that isn't Eversion, but the program is otherwise finished.
Link to EversionRipper on github[github.com]
This is a windows command-line program. You drop in a file, you answer a question, and out comes your sprites.
As for writing new sprites, while we technically can put in new sprites, I don't want to hack something together that assumes information in the file and sprite headers. How objects actually work in the game is a bit mysterious and a bit volatile. I'm free to answer any questions you may have about the programs or files !
Have fun everting !