Q: My iPhone 5 camera roll is empty, but under usage says 3.1GB - how can I delete?

Try resetting your iPhone to see if that clears out the reported usage.  If the problem continues, you may want to update your iOS via a wired connection to your computer (if available) as that seems to be more reliable than installing iOS updates over the air (IMO) ... and be sure to do a backup first, either to your computer (preferred) or to iCloud.

Is it specifically Camera Roll?  If you go into Settings/ General/ Usage/ Photos & Camera you should see a breakdown of the usage -- Camera Roll, Photo Library, and Photo Stream.  Confirm which of those three categories is taking up the space.

Perhaps you have pictures that you (at least at one time) synced through iTunes -- those would show up in the Photo Library category, and can be reduced by changing your sync settings in iTunes.

Do you back your photos up to iCloud?

A backup contains pictures that are in Camera Roll, but that would not impact reported usage on the device.  I suppose if the device needs to be restored, re-installing the backup would recover the Camera Roll but may not repair any condition where the usage is mis-represented (that could be a corruption that could find its way into the backup).

If you mean Photo Stream as a "backup", I think the OP said that it was off.

armccoy wrote:

 

Also, I read about iExplorer and tried a demo

Personally I get a bit nervous with these 3rd party apps that dig into the contents of my devices, so I can't comment on whether they work or not, or how to use them effectively.

For your situation, if the photo usage is being misrepresented then something could be corrupted beyond what a simple device reset can do.  You might do a backup (to iCloud or computer) and do a full restore of the iPhone and then load your backup (and apps & media, etc.) back on.  That may fix the issue, but if there is an underlying corruption somewhere, that problem could be part of the backup so you may end up having to start from scratch.

I had a similar issue where I had barely any photos on phone but then it was showing 7GB under Settings>General>Usage>Storage>Photos & Camera and then under Photo Stream. Having then copied all photos across to my computer I kept trying different on and off settings to try rectify and I finally found that it removed this when I went to Settings>Photos & Camera and switched the My Photo Stream option off  (at which point it asked me to confirm as: Turning off Photo Stream will delete all Photo Stream photos from your iPhone). When I then went to check in the usage setting it was gradually showing more free space as I checked over next few minutes until the Photo Stream had dropped right down. Don't know if this helps in your scenario but its just giving me a whole loada iphone back ;P

I've been having a similar issue. On my iPhone 5C it said that I had a bunch of pictures taking up 2GB of space, even though I had used Windows Explorer to move all of the pictures from my device onto my computer.  No pictures in my Photo Library, yet my phone was saying there was 2GB of space being used for pictures in the Photo Library.  After trying restarts and this and that, without success, I tried a third party app as suggested on LifeHacker (i-funbox). I was then able to access the DCIM folder that way, and there were a LOT more folders there visible, three of which contained a LOT of photos... 2GB worth.  I deleted them and... it got rid of 2GB of "OTHER".  Well, it's a start.  I'm sure the other pictures are there somewhere!

If you are trying to update to iOS 8, which requires 4-5 GB of free available storage through WIFI, and your not able to update because of this, I would suggest an update through iTunes which only requires 900MB ish. If it is a software glitch and you backup in iTunes, restoring the backup in iTunes will only bring the glitch back to the phone. I would suggest selecting the restore iPhone option in iTunes which will also update, and then do a MANUAL sync back onto the phone.

I deleted all my pics/vids from camera roll.  Turned off Photostream and iCloud Sharing.  My Photos app was completely empty, but usage showed 5GB usage in photo library.  After days of restarting my phone, I came across your post.

That you for referring ifunbox.  I had the same issue on my iPhone 5 and free'd up 5GB worth.