To be fair to Google, they really need "a perpetual, irrevocable, worldwide, royalty-free, and non-exclusive license to reproduce, adapt, modify, translate, publish, publicly perform, publicly display and distribute any Content which you submit" otherwise, they can't show your photos to other people. However, that doesn't mean I trust Google not to be evil.
In reality, if you post your pictures, people can keep them. The best you can do is to post reduced-size 'teasers' or spoil them with watermarking, logos or signatures. My own opinion is dramatic, and anathema to speculative commercial photographers: either share it, or don't. If your work is so good that people will pay for it, then put it in a commercial catalogue; don't put it out on a photo sharing site, and then whine if you think that someone printed it out to stick on their wall.
