I swear I remember seeing something on the news once where you could use a website to find out if a picture (e.g., that someone sent you, posted as their profile pic on facebook, etc.) is really a picture of them or if they grabbed it off the internet. If I remember correctly, you could upload the picture onto this website and, like a search engine using keywords, it searches the internet for that photo and shows you where it came from (if it came from a website).
Does anyone have any idea what website this is? Does this kind of thing even exist, or am I losing my mind? I googled it but came up with nothing.