When using the High Dynamic Range (HDR) feature of the Camera app, a normal non-HDR copy, will saved in addition to the HDR pic. This will result in a second picture for every photo you take with HDR turned on consuming twice the amount of storage. Additionally, your photo album will become cluttered with non-HDR copies. If you manually turn on the HDR feature, iOS should only save an HDR picture. The good news is that the annoying default behavior can be disabled.