A bitmap that is stored in compressed form using the RLE algorithm. SGI chromaticity ranges from 8 to 32 bits/pixel. The format is designed for use on Silicon Graphics workstations. It is also known as Irix RGB or IRIS.
A bitmap image in the Portable Any Map format that was originally developed for processing and storing several types of monochrome and color images without compression as well as grayscale images. Bitmap graphics data in a PNM file are stored using ASCII or binary structure.