Site changes
I've merged in a feature of a GreaseMonkey script that I've used for a long time: hovering over the ddl bar of an image highlights all other posts on the page that were posted by the same user.

It helps a lot when scanning index pages containing a batch post with a few individual posts interleaved; hover over one of the batches and you can see which ones aren't part of it. Similarly, if someone's posting something you're interested in, but it's scattered around the page, hover over one of them; you don't have to squint at each thumb or go into a user search to find "probably related" posts.

(feedback, style suggestions, etc. welcome)
You need to up the brightness of the highlight. I can barely see it at the moment.
It's clearly visible to me. Is your monitor calibrated strangely? #300 is significantly brighter than #000.
Can personaly barly see it as well, need to focus very much to see it.
I admit I do keep my screen fairly dark.

Does http://www.sendspace.com/file/1bffrs look fine on your screen?
It looks fine, it can be brighter, but I can see if nicely enough.
If I make it brighter, I have to make the resolution text brighter too.

+ The last Edit/Respond selection in post/show is now saved.
Works all right for me. Even on an 8 year old CRT monitor, the highlight's easily visible.
How about a different colour then?
If you have trouble seeing a 20% red, you should really fix your monitor calibration first...

I can try changing the star icon or something.
Changing the star icon colour might help with visibility.

Perhaps even changing the bar to display resolution/file size/rating without having to mouse-over? (But this is kinda changing the subject...)
That would make the index too busy.

I could make mousing over the thumb show the resolution (not just the bar), but I'd probably have to rewrite it in JS instead of the current CSS stuff. (I don't really find it very useful either way, myself...)
Just add it to your 'nice to have, but not important' job-flow.

Still interested in a colour change to the icon though.
+ Added order:random and "random" link at the bottom of the page. This sorts in a fixed random order. If you use this multiple times, you'll get the same ordering (for performance).

I added this because I noticed I kept seeing interesting posts I'd missed just by looking through the semi-random "show more" image search results, and post/random is a bit cumbersome.

+ Fixed unreadable links in quoted forum text.

+ Your own forum posts will no longer cause the forum to think you have unread posts.

+ Removed "atom" from the post menu. (This is linked in the <link> tags that any RSS/ATOM reader should find automatically.)

+ Don't clutter the menu with "moderate" for non-mods.

+ Added "image search" to the menu (this was a bit annoying to get to and I use it frequently).