How to Delete a Camera Roll From an iPhone
In addition to the iPhone's multimedia and application-running abilities, the device is also capable of taking photos and recording video. The photos and videos taken on the iPhone are stored in what is called the Camera Roll. While Apple provides no way to delete the Camera Roll in one step, you can quickly delete multiple photos and videos to clear out the Camera Roll.
Tap the "Photos" icon on your Home Screen to view all photos on the device.
Select "Camera Roll" to open the Camera Roll, which contains photos and videos you've taken with your iPhone.
Choose the boxed arrow icon in the bottom left-hand corner of the screen.
Scroll through your Camera Roll and tap on each photo or video that you'd like to delete. When finished, tap the "Delete" button. This will delete everything you selected.