Batch Photo WaterMark
Any time you upload pictures to a photo-sharing site--or even to your own personal Web site--you stand the chance of others using your work without permission. To prevent this theft, you can add a watermark to your photos with Corel Paint Shop Pro or a similar photo editor. If you don't have one of these programs, you could try a stand-alone tool like Batch Photo Watermark.
Batch Photo Watermark has a bare-bones interface. There's a Windows Explorer-like browsing panel on the left, a preview panel on the top right, and a panel on the bottom right that lists the image files you've chosen to work on. (The trial version of this software is limited to six image files at a time.) There are none of the menus you'd expect, just buttons that provide pop-up tips describing their function. This is a good thing, because otherwise it would be hard to know that the Export button is actually "Save As." The Help system is of little use; it's just a FAQ with poorly written instructions.
Interfaces glitches aside, it's not too hard to figure out how to add text to batches of photos at a time, resize them, or even rotate them. Unfortunately, copyright and trademark symbols don't seem to be available, and the program inserts the vendor's URL into your images without a clear way to remove it. (The Web site isn't clear on whether this is added in the trial version only.)
It's difficult to recommend Batch Photo WaterMark. The program costs $33 to license; you could pay a couple bucks more for the better-designed and Vista-compatible Visual Watermark, which lets you create secure PDFs, add trademark and copyright symbols, and more.