I've reverse engineered the majority of the data files in the space adventure / exploration game Nomad , published in 1993/1994 by GameTek. It's all published here: https://colinbourassa.github.io/media/nomad/ There's also a link to the GitHub repo for a utility that I wrote to browse the graphics a...

Here's the source to an .SPR decoder:

https://github.com/colinbourassa/imagexcel-decode

It covers only the sprite/palette formats described in this thread. I've tested it with JWALL*.SPR, KWALL*.SPR, PWALL*.SPR, SWALL*.SPR, and WWALL*.SPR, and it seemed to work fine.

--Colin