These commands are used for creating and accessing files defined by the PBMPlus toolkit, either PPM files for fully rendered images or PBM files for line images. PBMPlus files are a class of image store. The scanning direction is from top to bottom. PBMPlus files can be created in raw (binary) or plain (ASCII) formats. Due to the weaknesses of the PBMPlus library, read access to these files is not supported.