Why do my pictures take up so much space on my iPhone?

In usage, it says that photos and camera take up 10.8gb. I have a 16gb iPhone and 910 pictures. The thing I'm confused about is that on my friends phone she has more than 1000 photos but in usage it says pictures uses 2gb. How can I fix mine to save space?

Two things that take up space - videos and Photo Stream. Go through and delete photos you don't need, but especially videos. You can always turn Photo Stream off if it's on, and that will save space too. If your friend has a 32 or 64 GB iPhone that also might explain the difference.

Your friend might have low quality photos, the better the camera the more space it takes up, iphone 5 has HD video and a really good camera so that will take more space, just offload all your videos and pictures to your PC instead and the problem will be solved.

Because since the iPhone has a good camera the amount of memory each photo takes would be more than a phone with a worse camera.
If you have photo stream enable, it does not make a difference to the iPhones memory. It takes it off your iCloud memory which makes no difference to your iPhones hard drive.
Try deleting apps and photos that you don't need.

Just put a 32 gig sd card in your iphone and you will have a lot of space

I don't see how pictures could take that much space. I have 2248 pics taking up 448.3MB. I suppose you could have them re-synced to the phone. Of course have a backup handy.

I have no photos and I have a 32 gb iPad and it takes up 22.5 gb. Why does it do that?!