Can you tell me how to find person by his picture?

[Liam]

sometimes i use to search by its url on google and i find the person but not every time so if you know other way please tell me

[Mike1942f]

If you have name or some other connection, use Google Images to visually scan large selection that have those words associated with it. I have not found Google's image matching where you drop and image all that useful.
If you have a published picture, then TinEye will often find EXACT matches to all or part of the picture, but it is doing pixel by pixel match, not "hey this looks like the guy"
There is no online service I know of that will do the kind of facial feature matching that is done by huge commercial programs for terrorist search in airports.

[Tessa]

If you know their name look them up on Facebook. If you only know the first or last name, perhaps match up the picture with their profile picture.