Why PNG compression is that much slower than JPEG on Android?

Question

I\'ve been toying with Android Bitmaps a bit and found out, that PNG compression takes much more time than even highest quality JPEG one. Much much more. On my device it can

Answer 1

I've tested my project on emulator with much bigger pictures and though PNG compression was little slower, there was no drastic difference in performance. Therefore it should be due to the hardware acceleration, as told by BitBank in the comment.