MBM – Maximum bits: upto 24

Psion MultiBitMap (MBM) is the native file format for the Psion mobile computing solution products. Psion MBM files can contain one or more individual images. The MBM format supports grayscale or black and white images with 1, 2, 4, and 8 bits per pixel, or color images stored with 4, 8, 12, 16, and 24 bits per pixel. Individual images in an MBM can be stored in an uncompressed or compressed form.

GFX-View V3 can  read and display Psion MBM images in any format. Single MBM files can be saved. Grayscale or black and white image storage is with 1, 4, and 8 bits per pixel, and color images are stored with 4, 8, or 24 bits per pixel.

Note: MBM compression is a simple run-length encoding (RLE). RLE compression can have significant benefit for images with large regions of constant color, but less benefit for images (like photographs) that do not.