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.
It is used as a common format for bitmaps in operating systems environments based on the UNIX kernel. It is designed for use in many types of graphics. It can be used for all kinds of data with two-dimensional arrays. It covers the RGB-space and transparency levels.