Quality of JPEG vs PNG images

[mabezdek]

Hi,
I have a question about quality of images. The quality is set with equal alue for both (jpg and png) types, but internally it uses the imagejpeg method for JPG (quality from 0 to 100) and imagepng for PNG (there is quality option from 0 to 9 - lower bigger quality). So the quality for these types is completely different at the result.

What we can to do with that? Thank you.