While Windows Phone 8 10327 and higher (aka GDR2) does a great job of fixing the Other storage memory leak, there are still some quirks that are irritating a few users. The main complaint appears to be how Windows Phone handles auto-uploaded images to SkyDrive, or even if you manually mass upload photos and video.
In essence, when you upload photos to SkyDrive, they end up either in the 'Camera Roll' and 'Mobile Uploads' folders. You can then of course delete them from your device but believe it or not, Windows Phone holds onto them in Temporary storage for two weeks i.e. a SkyDrive cache.
That’s why some people have higher than normal Temporary storage numbers that cannot be cleared using apps like Nokia Storage Check. If you leave auto-upload for photos off, it will be quite low, usually less than 50MB in size (ours is at 33MB). If however you had a few hundred photos that were just processed, it could much higher.