My application has the user name and the user profile picture (from Facebook-SDK). When the user clicks on a button I want the application to make a notification to all the users who are in about 100 meter radius range. The notification will show the user his profile picture and his name. Will I need database for this? If yes, how can I upload the profile picture to the database? What is the function that makes the notification only to the users who are in the 100 meter radius range? Will the application even work if it doesn't display on the device? If not, how do I make this works? Thanks in advance!