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.
PGM is a storage format for grayscale images. Files in this format can be opened using software: ACDSee Photo Manager 14, ACD Systems Canvas 15, Corel PaintShop Pro X4. This type of file can be edited with a text editor. PGM files can be in two versions: P2 / P5. P2 are readable, P5 - to binary formats.