Add a new feature/function to my facebook app

Hi, I currently have a facebook application which posts a picture to the user's profile once allowed. Now I want to add another feature to the app. I want it to have an auto-tag feature. I want the app to automatically tag friends to the photo posted. On the number of friends to be tagged, let's discuss that later. That's all. Really simple job. Oh, I might also ask you to do other stuff related to my app, but just minor things. The main focus of this project is the auto-tag feature. Budget: 30-50$