# giftopnm - man - [phpMan] > **TLDR:** Convert a GIF file into a PNM image. > - Convert a GIF image to a Netpbm image pixel-for-pixel: `giftopnm {{path/to/input.gif}} > {{path/to/output.pnm}}` - Display version: `giftopnm {{-v|-version}}` *Source: tldr-pages* --- _Giftopnm_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown) General Commands Manual _Giftopnm_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown) ## NAME giftopnm - convert a GIF file into a PNM image ## SYNOPSIS **giftopnm **[**--alphaout=**{_alpha-filename_,**-**}] [**-verbose**] [**-comments**] [**-image=**{_N_,**all**}] [**-repair**] [**-quitearly**] [_GIFfile_] 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). This is a graphics format converter from the GIF format to the PNM (i.e. PBM, PGM, or PPM) format. If the image contains only black and maximally bright white, the output is PBM. If the image contains more than those two colors, but only grays, the output is PGM. If the image con‐ tains other colors, the output is PPM. A GIF image contains rectangular pixels. They all have the same aspect ratio, but may not be square (it's actually quite unusual for them not to be square, but it could happen). The pixels of a Netpbm image are always square. Because of the engineering complexity to do oth‐ erwise, **giftopnm **converts a GIF image to a Netpbm image pixel-for-pixel. This means if the GIF pixels are not square, the Netpbm output image has the wrong aspect ratio. In this case, **giftopnm **issues an informational message telling you to run **pamscale **to correct the output. ## OPTIONS In addition to the options common to all programs based on libnetpbm (most notably **-quiet**, see [ Common Options](index.html#commonoptions) ), **giftopnm **recognizes the following command line options: **--alphaout=_**alpha-filename_ **giftopnm **creates a PBM file containing the transparency information from the input image. This transparency image is the same dimensions as the input image, and each pixel of the transparency image tells whether the corresponding pixel of the input im‐ age is transparent. Black means transparent; white means opaque. If you don't spec‐ ify **--alphaout**, **giftopnm **does not generate a transparency file, and if the input image has a transparency channel, **giftopnm **simply discards it. If you specify **- **as the filename, **giftopnm **writes the transparency output to Standard Output and discards the image. See [**pamcomp**(1)](https://www.chedong.com/phpMan.php/man/pamcomp/1/markdown) for one way to use the transparency output file. ### -verbose Produce verbose output about the GIF file input. ### -comments With this option, **giftopnm **issues messages showing the GIF comments (A GIF89 stream can contain comments in comment extensions). By default, **giftopnm **ignores comment extensions. ### -image= This option identifies which image from the GIF stream you want. You can select ei‐ ther one image or all the images. Select all the images with **all**. Select one image by specifying its sequence number in the stream: **1**, **2**, **3**, etc. The default is just Image 1. A GIF stream normally contains only one image, so you don't need this option. But some streams, including animated GIFs, have multiple images. When you select multiple GIF images, the output is a PNM stream with multiple images. If you specify a single image, **giftopnm **must read and partially validate the images before that in the stream. It may or may not do the same for the images after it; see **-quitearly**. The **all **value was added in Netpbm 10.16 (June 2003). Earlier **giftopnm **can extract only one image. ### -repair This option makes **giftopnm **try to salvage what it can from an invalid GIF input. In particular, when **giftopnm **detects that the GIF input is invalid so that it is im‐ possible to determine what the pixels are intended to be, it produces a single arbi‐ trary color for all further pixels in the image. **giftopnm **processes the image from top to bottom, left to right, so this means the bottommost pixels will be this padding. **giftopnm **issues warning messages when it salvages an image in this way. Without this option, **giftopnm **fails when it detects invalid GIF input. Any output it produces is arbitrary, and typically is not a valid PNM image. It is fairly common for an image to be corrupted such that is started off as a valid GIF, but had the end of the file cut off. An interrupted network transfer tends to do this. In this case, **giftopnm**'s salvage operation will produce a valid PNM image of the proper dimensions, but with a single arbitrary color for the pixels that were left out of the file. This option was new in Netpbm 10.38 (March 2007). From 10.32 through 10.37, **giftopnm** always fails if it detects invalid GIF input. Before 10.32, it succeeds in the case of a truncated image, and replaces the missing pixels with arbitrary colors, not nec‐ essarily all the same (The pre-10.32 behavior wasn't actually intended by the design). ### -quitearly This option makes **giftopnm **stop reading its input file as soon as it has converted and output the images from the input that you requested. By default, **giftopnm **reads until the end of the GIF stream, ignoring any data after the images you requested. Two reasons _not_ to use this option: • The input file is a pipe and the process that is filling that pipe expects the pipe to take the entire stream and will fail or get stuck if it doesn't. • You want to validate the entire GIF stream. Two reasons to use this option: • It saves the time and other resources to read the end of the stream. • There are errors in the end of the stream that make **giftopnm **fail. This option has no effect if you also specify **-image=all** This option was new in Netpbm 10.35 (August 2006). Before that, **giftopnm **always reads the entire stream. ## RESTRICTIONS This does not correctly handle the Plain Text Extension of the GIF89 standard, since I did not have any example input files containing them. ## SEE ALSO [**pamtogif**(1)](https://www.chedong.com/phpMan.php/man/pamtogif/1/markdown), [**ppmcolormask**(1)](https://www.chedong.com/phpMan.php/man/ppmcolormask/1/markdown), [**pamcomp**(1)](https://www.chedong.com/phpMan.php/man/pamcomp/1/markdown), []() , [**ppm**(1)](https://www.chedong.com/phpMan.php/man/ppm/1/markdown). ## AUTHOR Copyright (c) 1993 by David Koblas (<_koblas@netcom.com_>) ## LICENSE As a historical note, for a long time if you used **giftopnm**, you were using a patent on the LZW compression method which was owned by Unisys, and in all probability you did not have a license from Unisys to do so. Unisys typically asked $5000 for a license for trivial use of the patent. Unisys never enforced the patent against trivial users, and made statements that it is much less concerned about people using the patent for decompression (which is what **giftopnm **does than for compression. The patent expired in 2003. Rumor has it that IBM also owns a patent covering **giftopnm**. A replacement for the GIF format that has never required any patent license to use is the PNG format. ## DOCUMENT SOURCE This manual page was generated by the Netpbm tool 'makeman' from HTML source. The master documentation is at **** netpbm documentation 13 September 2012 _Giftopnm_ _User_ [_Manual_(1)](https://www.chedong.com/phpMan.php/man/Manual/1/markdown)