[rab] Well, the buttons look better on my iBook screen! Something I will certainly need to remember next time I do some graphic design work... there is something in the OSX settings panel somewhere to change the colour balance to match that of a CRT; don't know if that would help.
[Projoy] That's not my fault. OK, so it is my fault that I insist on using those new-fangled PNGs rather than the old-school GIFs. I think I know of a workaround, but will be fiddly to apply.