ZDoom font/image tool
This is mainly used for converting image files to and from FON1/FON2 font formats.
The IMGZ format was created to overcome a deficiency in WinTex and offers no features that you can't also get with PNG.
You need Bison and Flex if you want to modify the lexxer and scanner. The project file is for Visual C++ 6. I haven't actually built this in ages, but it should still work. I just wanted to get it onto GitHub.