Atheist Antichrist

I'm having issues with .iff and .lbm files, an ancient game (Independence War 2 - Edge of Chaos) uses the .iff and .lbm filetype(s) but I'm getting errors when I try to save to that format I've downloaded the requisite filetype plugins, but I'm missing something. I don't want to install Paintshop or photoshop if I can help it. Has anyone put together a Filetype plugin bundle? I didn't see one in that part of the forum, but thought maybe someone put one together and I missed it.