RGB2PCT(1)

✨ rgb2pct(1) ✨

okay so bestie, listen 💖 this one is rgb2pct, and it lives in the GDAL family of utilities. She's giving "glow-up for your images" energy and honestly? we're obsessed.

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NAME

rgb2pct — Convert a 24bit RGB image to 8bit paletted. 🎀

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SYNOPSIS

rgb2pct [--help] [--help-general] [--creation-option OPTION]
           [-n colors | -pct palette_file] [-of format] <source_file> <dest_file>

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DESCRIPTION

So here's the tea 🫖: this utility will compute an optimal pseudo-color table for a given RGB image using a median cut algorithm on a downsampled RGB histogram. Like, it's doing MATH on your colors, and the math is cute. Then it converts the image into a pseudo-colored image using that color table. ✨

And the conversion? It utilizes Floyd-Steinberg dithering (that's error diffusion, iykyk) to maximize output image visual quality. Basically it makes your 8bit look way better than 8bit has any right to look. periodt. 💅

NOTE: rgb2pct is a Python utility, and is only available if GDAL Python bindings are available. no bindings, no vibes, no service. 😭

TIP: Equivalent in new "gdal" command line interface: See gdal raster rgb-to-palette.

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✨ OPTIONS ✨

• --help — Show this help message and exit. the classic. 🙈
• --help-general — Gives a brief usage message for the generic GDAL commandline options and exit. it's the general-vibes help, not the specific-vibes help 🦋
• -n <color> — Select the number of colors in the generated color table. Defaults to 256. Must be between 2 and 256. so like, don't get weird with it. 💀
• --creation-option OPTION — Optional creation parameters for the GeoTIFF driver, for example "COMPRESS=LZW". Can be specified multiple times. stack 'em up bestie 🔥
• -pct <palette_file> — Extract the color table from <palette_file> instead of computing it. Can be used to have a consistent color table for multiple files. The <palette_file> must be either a raster file in a GDAL supported format with a palette or a color file in a supported format (txt, qml, qlr). consistent palette across your whole folder = main character energy 👑
• -of <format> — Select the output format. If not specified, the format is guessed from the extension. Use the short format name. Only output formats supporting pseudo-color tables should be used. don't set yourself up like that 💖
• <source_file> — The input RGB file. the before picture 🌸
• <dest_file> — The output pseudo-colored file that will be created. the after picture ✨

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RETURN STATUS CODE

The program returns status code 0 in case of success, and non-zero in case of error (non-blocking errors emitted as warnings are considered as a successful execution). so 0 = slay, anything else = 🚨

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EXAMPLE

If it is desired to hand create the palette, likely the simplest text format is the GDAL VRT format. In the following example a VRT was created in a text editor with a small 4 color palette with the RGBA colors 238/238/238/255, 237/237/237/255, 236/236/236/255 and 229/229/229/255. look at her, little handcrafted palette, an icon 🎀

$ rgb2pct -pct palette.vrt rgb.tif pseudo-colored.tif
$ more < palette.vrt
<VRTDataset rasterXSize="226" rasterYSize="271">
    <VRTRasterBand dataType="Byte" band="1">
        <ColorInterp>Palette</ColorInterp>
        <ColorTable>
        <Entry c1="238" c2="238" c3="238" c4="255"/>
        <Entry c1="237" c2="237" c3="237" c4="255"/>
        <Entry c1="236" c2="236" c3="236" c4="255"/>
        <Entry c1="229" c2="229" c3="229" c4="255"/>
        </ColorTable>
    </VRTRasterBand>
</VRTDataset>

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AUTHOR

Frank Warmerdam <warmerdam@pobox.com> 🫶

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COPYRIGHT

1998-2026

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and that's the whole page bestie, no cap 💜 this GDAL manual page is dated Aug 18, 2026, and yeah she's still going strong. rgb2pct(1) — ate and left no crumbs. 🌈⭐