Take this scenerio....   a few months ago , my friend lost her i phone . on that i phone she had some pictures of her self well.... in the buff.... she wants to know if they are out on the internet, and wants to use google reverese image search to find them. She has a copy of them.  will google keep a copy of pictures she uploads thru reverse image search.

If she does, how safe are they, who views the image logs. 

How long will these pictures stay at Google. I don't see how an image query can help google improve its results. ITs not like a data querry , were what a person types matter.  Google Privacy policy is really not clear on any of this at all.