I noticed today that the lovely new dragon-and-gears logo was loading very slowly every page load. I saved a copy to inspect it, and noticed that it's a PNG that's only lightly compressed. The lovely thing about PNG though is that you can change the compression and it stays pixel-perfect, so out of curiosity I loaded it up in GIMP and resaved it with all the non-destructive compression options, and to my delight it crushed it down from about 380KB to about 62KB, a nearly 85% bandwidth savings.
Being an image that loads on every page, I humbly suggest you consider recompressing it. (The only disadvantage is that it takes slightly more processor time to decompress it on the reader's side, but the difference is invisible on even old computers, so it's an excellent tradeoff here.) If not for your bandwidth savings, then for the selfish reason that it would improve my page load speed.