Hi bit of a silly question.
Are there any png transparency issues with backgrounds to submit buttons or inputs of type image? Or do they behave fine just like img tags with a png image as the source.
I understand for IE6 you need a hack for png transparency to work.
Yes, if you have png files and you are under IE6, you will witness such problems. But there are solutions too; one being as follows:
http://jquery.andreaseberhard.de/pngFix/
By the way there is no need to use png for input type buttons, etc unless you really need it.
Another issue is metadata which can be contained in png file. If png contains it, then in IE browsers you'll see a bit different colors.
It can be fixed easily. You just need to save your png correctly (disable metadata).
I ran into this issue recently and converted the button images to Gif. There is a minor loss of fidelity, as you have to get by with 256 colors, but transparency works without any hacks.