94 photos and 463 MB
Are there any photos in your "Recently Deleted" album? These still count towards your photos storage.

Try signing into iCloud and uploading the photos to iCloud Photo Library (enable at Settings > iCloud > Photos). The size of your iCloud Photo Library (Settings > iCloud > Manage Storage) should represent the size of the photos on your phone.

Some people have suggested performing a hard shut down (hold Power and Home buttons for 5 seconds until screen goes black) to reset Storage usage info.