# man > ppmtobmp(1) > **TLDR:** Convert a PPM image to a BMP file. > - Convert a PPM image to a BMP file: `ppmtobmp {{path/to/file.ppm}} > {{path/to/file.bmp}}` - Explicitly specify whether or not a Windows BMP file or an OS/2 BMP file should be created: `ppmtobmp -{{windows|os2}} {{path/to/file.ppm}} > {{path/to/file.bmp}}` - Use a specific number of bits for each pixel: `ppmtobmp {{-b|-bbp}} {{1|4|8|24}} {{path/to/file.ppm}} > {{path/to/file.bmp}}` *Source: tldr-pages* --- _Ppmtobmp_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown) General Commands Manual _Ppmtobmp_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown) ## NAME ppmtobmp - convert a PPM image into a BMP file ## SYNOPSIS ### ppmtobmp [**-windows**] [**-os2**] [**-bpp=_**bits_per_pixel_] [**-mapfile=_**filename_] [_ppmfile_] Minimum unique abbreviation of option is acceptable. You may use double hyphens instead of single hyphen to denote options. You may use white space in place of the equals sign to sep‐ arate an option name from its value. ## DESCRIPTION This program is part of [**Netpbm**(1)](https://www.chedong.com/phpMan.php/man/Netpbm/1/markdown). **ppmtobmp **reads a PPM image as input and produces a Microsoft Windows or OS/2 BMP file as out‐ put. ## OPTIONS In addition to the options common to all programs based on libnetpbm (most notably **-quiet**, see ]8;;index.html#commonoptions\ Common Options]8;;\ ), **ppmtobmp **recognizes the following command line options: ### -windows Tells the program to produce a Microsoft Windows BMP file. (This is the default.) ### -os2 fault). ### -bpp and 24 are possible. By default, **ppmtobmp **chooses the smallest number with which it can represent all the colors in the input image. If you specify a number too small to represent all the colors in the input image, **ppmtobmp **tells you and terminates. You can use **pnmquant **or **ppmdither **to reduce the number of colors in the image. Before Netpbm 10.85 (December 2018), **ppmtobmp **ignores this option if the input is PBM and produces a BMP with 1 bit per pixel. With these versions, if you want more than that, use **pbmtopgm **to convert the PBM to PGM first. ### -mapfile=_ This identifies a file to use as the BMP palette (aka "colormap"). In one BMP subfor‐ mat, the BMP stream contains a palette of up to 256 colors, and represents the image raster as indices into that palette. Normally, **ppmtobmp **takes care of computing a suitable palette, but if you are going to dissect the BMP output in some way, you may want certain values for the palette indices. E.g. you might want red to be 13, where **ppmtobmp **would (arbitrarily) choose 39. In that case, you can construct the palette yourself and use this option to tell **ppmtobmp **to use your palette. This option does _not_ control what colors are in the output. The colors in the output are exactly those in the input, and the palette you supply must contain at least all the colors that are in the input. You can use **pnmremap **to adjust your input image so that it contains only colors from your palette. The palette file is a Netpbm format file with one pixel per palette entry. Each pixel must have a distinct color (no repeats). The order of the BMP palette **ppmtobmp **gener‐ ates is the order of the pixels in the palette file, going from top to bottom, left to right. A BMP palette may have at most 256 colors, so the palette file must have at most 256 pixels. You may find **pnmcolormap **useful in generating the palette file. **pamseq **too. In the case of grayscale image, if you are processing the BMP image, it may be convenient for you to have the actual gray values in the raster part of the image rather than arbitrary indices into a palette. There is no BMP format specifically for that, but you can achieve it by using a palette in which each index is equal to the indexed gray value, and then ignoring the palette when you process the BMP image. Here is an example of doing that: $ pamseq 1 255 > mapfile.pgm $ ppmtobmp -mapfile=mapfile.pgm input.pgm > output.bmp This option was new in Netpbm 10.45 (December 2008). ## NOTES To get a faithful reproduction of the input image, the maxval of the input image must be 255. If it is something else, the colors in the BMP file may be slightly different from the colors in the input. Windows icons are not BMP files. Use **ppmtowinicon **to create those. ## SEE ALSO [**bmptoppm**(1)](https://www.chedong.com/phpMan.php/man/bmptoppm/1/markdown), [**ppmtowinicon**(1)](https://www.chedong.com/phpMan.php/man/ppmtowinicon/1/markdown), [**pnmquant**(1)](https://www.chedong.com/phpMan.php/man/pnmquant/1/markdown), [**ppmdither**(1)](https://www.chedong.com/phpMan.php/man/ppmdither/1/markdown), [**pnmremap**(1)](https://www.chedong.com/phpMan.php/man/pnmremap/1/markdown), [**ppm**(1)](https://www.chedong.com/phpMan.php/man/ppm/1/markdown) ## AUTHOR Copyright (C) 1992 by David W. Sanderson. ## DOCUMENT SOURCE This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at **** netpbm documentation 20 December 2018 _Ppmtobmp_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)