#Unsupported TGA formats
TGA is a format all by itself, and as far as I know, only comes two ways,
compressed and uncompressed, unless you want to start getting into pixel depth,
but a TGA is a TGA. the rest of your question is a can of worms. Did you have
any particular software in mind? Most paint and raster based image programs
support many of the common formats, or can easily be converted from one to
another until you find common ground.