I believe it is tineye you are asking about.  The website link is provided.  After you bring up tineye, you then go to a webpage (like Eros) with pictures. Copy the url address of the picture.  Plug that url address into the url field in tineye and voila, tineye tells you if they find the image on another website.

I seem to have missed the discussion of what is tinyeye and how to use it, or even where to find it.  Is anyone willing to give me some clues about this?

Thanks in advance.

the rest should be fairly obvious