I would suggest background too.
glacier_bg.jpg is 350 Kb, and for 56k users like me... and for ppl who has restricted Bandwith on server... can be a very pain.
Don't worry if it lose a bit of quality, would be perfect if these images are less than 50 Kb, it's a backgroup ppl won't "study" the image there.
I would try to compress them myself, but since it's always better to work on original BMP it's better u do it.
EDIT: About links, write it in first post too, can help.
I just converted header_bgx.png in header_bgx.jpg, result:
From 780 Kb using PNG to less than 100 Kb due to JPG, working without even editing rotate.php file.
That's lot nice, compression was just 75% and not visible differences in quality.
I also Compressed the background from 350 kb to 130 Kb. But lossing visible quality (even if not much).