I would like to start using pngquant library in our product to improve our custom png compression. But png quant is lossy and it is going to be a hard sell. The main objection that I will get is we can't loose colors/quality. Are there any samples/cases when png quant algorithm produces compressed png images with visible loss in quality?
2 Answers
0
votes
The pngquant library produces images with (in my opinion) quite good quality. You can adjust it with the parameter
--quality min-max Instructs pngquant to 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 stdout, 24-bit original will be output) and pngquant will exit with status code 99.
min and max are numbers in range 0 (worst) to 100 (perfect), similar to JPEG. pngquant --quality=65-80 image.png
(from https://pngquant.org)
I have not seen an in-depth quality comparison with other lossy codecs, but you can always test if it suits your needs, and compare it with JPEG, JPEG2000 or others.
0
votes
I found that loss is noticeable when gradients with wide range of colors is used. http://the-coderok.azurewebsites.net/2015/09/23/Example-of-noticable-loss-in-image-quality-that-was-compressed-with-PNG-quant/
