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.
PPM is a simple format for storing images portable pixmap: color (PPM), grayscale (PGM) and black and white (PBM). These formats can provide an intermediate representation of the data when converting raster image files listed three types between different platforms. PPM format was developed by Jeff Poskanzerom.