I replaced the default photography in the theme with some of my own pictures last night. For some reason, they’re not as sharp as I’d like. Compression could be better too. I know about this, and it’s on The List of Things to Do (along with nine zillion other things). They also need alt text, which will probably need theme support.
Interestingly enough, while I wasn’t setting out to set a theme with the pictures, most of the involve water in some way.
Update, 8/18 11:16 PM
I’ve updated the images. The problem was that when I exported them out of Aperture, I didn’t notice the export was set to the Fit Within 640 px preset. I’ve made a new preset for header images, but noticed it still generates very large files. I’ll need to do some experimenting with compression settings. For now, running them through Photoshop, and using the Save for Web and Devices setting did the trick. I’d still like to be able to add alt text, even though the images are more decorative than informative.