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Picture Shark it's an easy but powerful image watermarking tool.

I use it very often to watermark my pictures at my website, Dandandin.net, and has an ease of use unparalleled with its competitors. Check the screenshot (click to enlarge):

You can download the version 1.0 released on May, 26 2002, from here:

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It's free for personal use, but commercial use it is "temporarily" allowed 

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