Using pictures from google images

So, is it legal to use pictures found on google images for example to create logo for my site? If I would use for example the iphone logo, can I get into trouble? Or the worst thing that they might do to me is to tell me to change it.

Please only serious answers.

According to this horror story it could land you in hot water:

Would depend on the image. Some may be royalty free, but in general assume it's copyrighted and that they could DMCA/etc you for using it.