I was browsing the internet the other day and I came across this site and thought it was very useful so I thought I would post it up here
TinEye – http://www.tineye.com
its search engine however instead of typing text of what you want to search for you upload or provide a link to an image you want to look for and it will find images based on that image
for example you see someone has posted a picture of their desktop that you like the back ground image to however it has icons, etc on it, you can upload it to TinEye and if an image that looks the same is in its database then it will show you list of results.
so say I saw this and wanted to to find the original image.
I could upload it to TinEye and get the original image
or put this in
and get this
its also useful if you have an image and want to see if you can get it in a higher resolution.
From the TinEye website
What is TinEye?
TinEye is a reverse image search engine. You can submit an image to TinEye to find out where it came from, how it is being used, if modified versions of the image exist, or to find higher resolution versions. TinEye is the first image search engine on the web to use image identification technology rather than keywords, metadata or watermarks.