Recently I've run into a need to develop some php generated images. The nature of the generated images fits much nicer with gif or png type graphics than it does with jpeg. I can generate png and jpeg via the GD image library in PHP. Older versions supported gif, but it is now breaking trademarked compression schemes.
Is png well supported among browsers(i know the advanced features aren't, but that's ok), or should I go for the less preferable jpeg method?
PNG is supported by all the major browsers (Opera 3+/IE 3+/NN 4+/Konqueror/ Icab). I don't know of a single big browser that doesn't support PNG. All the modes of PNG may not be supported, but I'm almost dead certain you'll have no trouble with the GD PNG library.