Alias PIX is a raster image file format. It uses RLE compression, and supports truecolor and grayscale images.
ImageMagick calls Alias PIX Alias/Wavefront RLE image format. This is potentially confusing, because a different format, RLA, is also associated with Alias|Wavefront, and also uses RLE compression.
An Alias PIX file has a 10 byte header, followed by the pixel data.