That's a good simplified explanation, Sionainn. :) cat - if you'd like more detailed info about each format, Min wrote up an explanation of the most common
image file formats.
And in this case, the reason for PNG files might in fact be a restriction of the online store...
I just wanted to add that I really appreciate the extension! :D
How are you all going with designing the Ober Mascots? I've got a Destroyer Pig well on the way, and I've finally managed to come up with something I like for the Dreamies Squirrel, but I'm still playing with the others - it's just too much fun! ;D
I also have a question - I've done a Penguin sketch, but I'm not quite sure -
Does he seem a little too unhappy? (Edit: Oh, and I know he's a little rough - I just work better starting out that way. :P)