---
name: "pngnq"
section: "1"
platform: "linux"
package: "pngnq"
version: "1.1+ds-3"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/pngnq"
---

# pngnq(1)

quantize png images

## NAME

pngnq - quantize png images

## SYNOPSIS

**pngnq \[-vfhV\]\[-s** *sample\_factor* **\]\[-Q** *dither* **\]\[-g** *gamma* **\]\[-e** *extension* **\]\[-d** *dir* **\]\[-n** *colors* **\]\[** *inputfiles* **\]**

## DESCRIPTION

**pngnq** quantizes a 32-bit RGBA PNG image to an 8 bit RGBA palette PNG using the neuquant algorithm. The output file name is the input file name extended with "-nq8.png" or a specified extension.

The "input files" defaults to standard input if not specified. If standard input is being processed the output is sent to standard output.

## OPTIONS

- \-d dir

  Tells pngnq to put output files in a directory other than the one the input files are in.

- \-e extension

  Specifies the new filename extension. Defaults to "-nq8.png". Pngnq drops .png from the original filenames. If you set the argument of the -e option to .png and choose the -f option the input file will be overwritten.

- \-f

  Force overwriting of files.

- \-g gamma

  Set the image gamma correction. If not present, uses the png file's gamma or defaults to 1.0.

- \-h

  Print program help.

- \-n colors

  Specifies the number of colors to quantize to. Defaults to 256 which is the maximum. The minimum here is 2.

- \-Q dither

  Choose a dithering method: n = no dither (default), f = Floyd Steinberg dithering.

- \-s sample factor

  Sample factor. The neuquant algorithm samples pixels stepping by this value. The default value of 3 gives good results. Higher values sample less of the image pixels and thus are faster but less accurate. A factor of 1 samples every image pixel.

- \-v

  Verbose mode. Prints status messages.

- \-V

  Print version number and library versions.

## BUGS

Does not deal correctly with greyscale alpha images with low bit depths, but these wont benefit from quantizing.

## AUTHOR

Stuart Coyle \<stuart.coyle@gmail.com\>

## SEE ALSO

**[png(5)](/png/5.md)**