You can take the image you want and save it to your computer. Then go directly to http://images.google.com/
From there, click on the camera icon to upload the image. Or if possible, just paste the url and avoid the save-and-upload steps.
Also do a web search for TinEye. You can get a lot of results with that.
These suggestions are around in PeachyForum. If you browse long enough, you'll find a lot of other interesting suggestions as well.