PNG will always do a bad at compression. PNG is deflate encoded, but without the ability to rearrange pixel data to work with deflate's strengths. It will pic

PNG will always do a bad at compression. PNG is deflate encoded, but without the ability to rearrange pixel data to work with deflate's strengths. It will pick RGBA, which mixes the "entropy" data for each color channel together. PNG was born out of the necessity to replace the (at the time) patent encumbered GIF. PNG has a different purpose, and was designed to get something working fast.