pngquant converts 24/32-bit RGBA PNGs to 8-bit palette with alpha channel preserved. Such images are fully standards-compliant and are supported by all web browsers.
Quantized files are often 60-80% smaller than their 24/32-bit versions.
This utility works on Linux, Mac OS X and Windows. This is the official
- batch conversion of multiple files:
- Unix-style stdin/stdout chaining:
… | pngquant - | …
Improvements since 1.0
Generated files are both smaller and look much better.
Significantly better quality of quantisation
- more accurate remapping of semitransparent colors
- special dithering algorithm that does not add noise in well-quantized areas of the image
- supports much larger number of colors in input images without degradation of quality
- gamma correction and optional color profile support (output is always in gamma 2.2 for web compatibility)
Refactored and modernised code
pngquant -h for full list.
max are numbers in range 0 (worst) to 100 (perfect), similar to JPEG. pngquant will use the least amount of colors required to meet or exceed the
max quality. If conversion results in quality below the
min quality the image won't be saved (if outputting to stdin, 24-bit original will be output) and pngquant will exit with status code 99.
pngquant --quality=65-80 image.png
Set custom extension (suffix) for output filename. By default
-fs8.png is used. If you use
--ext=.png --force options pngquant will overwrite input files in place (use with caution).
-o out.png or
Writes converted file to the given path. When this option is used only single input file is allowed.
Don't write converted files if the conversion isn't worth it.
Speed/quality trade-off from 1 (brute-force) to 11 (fastest). The default is 3. Speed 10 has 5% lower quality, but is 8 times faster than the default. Speed 11 disables dithering and lowers compression level.
Disables Floyd-Steinberg dithering.
Controls level of dithering (0 = none, 1 = full). Note that the
= character is required.
Reduce precision of the palette by number of bits. Use when the image will be displayed on low-depth screens (e.g. 16-bit displays or compressed textures in ARGB444 format).
Don't copy optional PNG chunks. Metadata is always removed on Mac (when using Cocoa reader).
Print version information to stdout.
Read image from stdin and send result to stdout.
Stops processing of arguments. This allows use of file names that start with
-. If you're using pngquant in a script, it's advisable to put this before file names:
pngquant $OPTIONS -- "$FILE"
pngquant is dual-licensed: