Can I use images from Google on my website?
If you have permission, yes. If you don't, unless that picture is in the public domain, absolutely not. Just because an image is on Google or isn't watermarked, doesn't mean you have the ability to use it. If you use an image that you don't have the rights to do so, you are committing copyright infringement in using the image and can wind up paying some heavy legal fees down the line.