Easy Way to Find a Facebook profile from a pictureGoogle images search will help you with it. At this point, you have to options: to upload the picture from your computer or to insert the URL of the existent online image. To get the URL, you should simply right-click the image and choose "copy image address" and then, paste it into the Google images search.
After you hit the "search" button, you will be given a list of results. Scroll down until you find the link o Facebook to make sure that is the necessary profile. Check out the tutorial on reverse image search here.
Tricky wayIf that method does not help, try out a more complex one. This works only if you have an online picture with an existent URL. So, get the image address with a right click. In this long line consisting of different numbers, you should extract the second to the last one. For example if you saved it as 61580_10173981_7375_n.jpg, so here the middle number i.e. 10173981 is the profile ID from a Facebook user's profile.
Feeling like a hacker, eh? Well, the last step you should take is to add this middle number to the Facebook address. For example: http://www.facebook.com/people/@/10173981. After hitting "enter" button, the needed profile will be instantly found. Although this method is not automated and takes more time, it guarantees you finding the right person.
If nothing really helps, try to look for other reverse email look up services that offer reverse image search. There are many ways you could find a Facebook profile from a picture, but always be careful with copyright law.