At the risk of, once again, outing myself as tragically out of touch,…  just how long has Google had a search function based on image files??   

Only just noticed that Google Images allows you to drag&drop an image onto their page, and it will search for image files that are similar in appearance, rather than searching for similar text.  

!!Caution!! do not drop your own photo on the page – it may be disturbing.    Seems that, to my computer, I appear something similar to either Albert Einstein …or Marilyn Monroe.

(clearly, they've not quite worked the bugs out)