Watermarker
Don Southard is a really clever guy. He comes up with some amazing little solutions for getting more done on your Mac and he's also a really fine writer with his pieces over at MacStories. Don just recently released a new application for the Mac, Watermarker. I like it. It's a simple application that consistently applies watermarks to images. My wife is using it every day right now as she writes her ongoing series about Christmas ornaments. If you want an easy way to watermark photographs and want to support a standup guy, check out Watermarker.