Codec Request: pngquant

[gowy222]

Is your feature request related to a problem? Please describe.
oxipng speed is to slow if img > 10MB
500KB png file still need 2.3s.
The compression ratio is only about 20-30

however..
[pngquant](https://pngquant.org/) is a PNG compressor that significantly reduces file sizes by converting images to a more efficient 8-bit PNG format with alpha channel (often **60-80%** smaller than 24/32-bit PNG files). Compressed images are fully standards-compliant and are supported by all web browsers and operating systems.

lets try this?

[jamsinclair]

This library focuses on ports of existing codecs from another project, https://github.com/GoogleChromeLabs/squoosh/tree/dev/codecs.

I don't have the bandwidth myself to work on this, but I would welcome and support any PR attempts to add pngquant.

To run Oxipng faster, I would suggest making sure the multithreaded code is running correctly

• https://github.com/jamsinclair/jSquash/tree/main/packages/oxipng#activate-multithreading

It may be possible to get better compression by adjusting the compression level https://github.com/jamsinclair/jSquash/blob/main/packages/oxipng/meta.ts#L28