I almost always put my name on an image. That'll keep most people from using it and saying it's theirs. I don't mind if someone copy's my images to his/her HD or even prints them for personal use. If my name is on it that's enough. If someone sees one of my images and likes it and sees my name he/she might even go search for more of my work. That's also a benefit of marking images.

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(")(")This is Bunny. Copy and paste bunny into your signature to help him gain world domination.