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.
Format for representing colors in the three primary colors (red, green and blue), each of which has 255 gradations. In contrast to the standard RGB, it allows you to change the transparency of the entire image using the opacity parameter. It is less flexible in terms of transparency settings than RGBA.