The advantages of the png files is that they support transparency and therefore also look good on a dark theme (background).
Also Tony redesigned the Eclipse Save icons that they young developer which never saw a floppy disk, can related. The save icon looks now a bit like a SD card.
Tony provided more icons, e.g. for JDT, Ant JFace, etc. I hope that I can also replace more icons in the platform, especially the gif files used by JDT look very ugly on a dark background.
Thanks again to Tony for this great contribution.