IFF-PBM

Overview
IFF-PBM is a raster image file format, based on the IFF container format. PBM stands for Planar BitMap.

Identification
The ASCII strings " ", " ", and " " appear near the beginning of the file.

Software

 * Netpbm
 * XnView

Sample files

 * http://samples.libav.org/image-samples/ASH.LBM