Manage Storage > No Data (iPhone 5s on iOS 7)

I'm trying to help a friend of mine.

She has a 32GB iPhone 5s, running iOS 7. When she goes into Settings > General > Usage > Storage - Manage Storage, many of the Apps listed have "No Data" next to them. For example: Passbook, Voice Memos, Voicemail, Music, Videos, Photos & Camera all show as having "No Data".

She has thousands of photos in her Camera Roll, so "No Data" is clearly an error. Why is it happening? Why is it showing "No Data" when that isn't the case? What can she do to make her iPhone 5s show the amount of data each app is using, like it's supposed to?

Thanks for your help.