I still love .png, lossless compression
WAY smaller when taking screenshots of your desktop with very few different colors without artifacts. For ingame-screenshots however (large amount of colors) it is bigger than jpeg.
I know there are lossless operations for jpeg, but I use png for screenshots of my desktop with CPU-Z and shit, as mentioned before, way smaller and no artifacts around text.
I like how it's hdpdemo.
jpg 