Can anybody recommend a good method of bulk converting a large amount of PNG-24 files to PNG-8 with as little loss of quality as possible and maintaining transparency?
I've tried ImageMagick but the resulting images weren't quite as crisp quality as I'd like. Using Paint.NET I was able to achieve far better results, but I can't bulk process with this tool as far as I know.
The settings I used with ImageMagick in case there's better options to use:
convert file.png -depth 4 file-output.png
I've also been playing with OptiPNG, but I haven't discovered a was of making sure the output images are PNG-8.
Best Answer
pngquant is exactly the tool for this. It generates palettes better than ImageMagick.
This will convert all png files in current directory, and automatically choose number of colors to achieve quality similar to 90%-quality JPEG.
(if it doesn't accept the
--quality
switch it means you have terribly outdated low-quality version and you should upgrade).