Quick Look is easily one of our favourite features in Mac OS X, but it would be nice if it had a little more info about the photo you're viewing. This free plugin adds pixel dimensions and file size to Quick Look's title bar.
Just head to the link below, download the ZIP file under "Build & Install", and extract the plugin to
~/Library/QuickLook (you may need to create the folder if it doesn't exist). Restart Quick Look by running
qlmanage -r in a Terminal.
When you reopen the Finder, invoke Quick Look to see a bit more information about the image. While you're at it, check out these other awesome plugins and tools to beef up Quick Look.