I developed an app that makes a photo and submits it with some text to my web service. Now when my app is running (even in a background mode) the battery drains in 4 hours and my iPhone is getting really hot. I thought it may be a problem with the device but after visiting an Apple Store they said the battery is fine and that the problem is in the app (I didn't say that it was my app). They said that it is running at full resources all the time.
Could you advice or give some hints how to manage resources on iPhone with ObjC?