If you are looking to add watermark to Images which were photographed by you in order to make sure no one others can use them, then check out Watermark Tool which is a online watermarking software completely free and instant.
The Online tools allows you to personalize the image with different watermarking options like Text Adding , Font Selection, Text Size, Position, Text Colour, Text Transparency & Box Color. You need to browse the images you want watermark with multiple images upload option and then complete this process.
Great watermark tool, but i prefer using picmarkr.com online free watermarking program as its easy and fast.
Moreso you can easily link Flickr, Facebook and Picasa images and photos with it, also you can easily promote your watermarked images for traffic to your website and blog via flickr image hosting and sharing
Thanks for sharing Amit