Yes, and it doesnt lose quality like JPG.
Compared to a high color JPG, its good compression and looks a million times better then jpg. JPG tends to screw up text in a picture, which is why I use PNG or GIF.
Compared to a gif, which is 256 color, the compression is alot better.
PNG also supports all the nifty things like animation, transparancy, ec..
PNG can be high color like JPG, or 256 like gif. It replaces both of them, because the compression and quality is much better.