This program is part of Netpbm.
bmptopnm reads a Microsoft Windows or OS/2 BMP file as input. and produces a PBM, PGM, or PNM image as output. If the input is colormapped and contains only black and white, the output is PBM. If the input is colormapped and contains only black white and gray, the output is PGM. Otherwise, the output is PPM.
This program cannot convert BMP files with compressed (run length encoded, JPEG, PNG) image data. It recognizes the compression and issues an error message.
Before Netpbm 10.18 (September 2003), this program could not convert BMP images with the BI_BITFIELDS format ("compression type"). It would recognize the format and issue an error message.
This program cannot convert OS/2 BMP files with 16 bits per pixel (only because the author did not have a complete specification for them). It recognizes the format and issues an error message. Before Netpbm 10.16 (June 2003), it also could not convert Windows BMP files with 16 bits per pixel.