TGA is a raster graphic format. It was originally created by Truevision Inc. for graphics cards has its own production in 1984, but later became popular on a variety of platforms, especially in the field of video editing, animation. Format supports color depths 1-32 bits per pixel. There is support for alpha channels, compression RLE.
PCX is standard presentation graphics developed by ZSoft Korporation. Used graphics program ZSoft PC Paintbrush for MS-DOS, word processing and desktop publishing applications, such as Microsoft Word and Ventura Publisher. Not as popular analog BMP, although supported by specific graphics editors such as Adobe Photoshop, Corel Draw, GIMP and others.