Yep, I am having this same problem. I did not pull my photos and videos off for several months. I noted photo space up to 7GB. So I pulled off all photos and videos in iPhoto and selected delete originals. Space did not change. So, I deleted ALL photos off the iphone so that the photo album is empty. That dropped space from 7GB used to 6.7GB used I have not yet tried restore from backup. But, from your experience is sounds like that may not work. I guess notes will sync to iMail? Wish was a way to manually delete.
The links below have instructions for deleting photos.
iOS and iPod: Syncing photos using iTunes
iPad Tip: How to Delete Photos from Your iPad in the Photos App
Another Way to Quickly Delete Photos from Your iPad (Mac Only)
How to Delete Photos from iPad
How to: Batch Delete Photos on the iPad
(With iOS 5.1, use 2 fingers)
How to Delete Photos from iCloud’s Photo Stream
OK! so after trying everything I could find to solve my same problem... I finally found one that worked!!
This person mentions a software called DiskAid... and that it what I had to use!!
You open up the software and then click the folder "file system" then "camera roll".... on mine it popped up with a bunch of random files, I deleted them all... since I had them already saved... I have no idea where or how these files were there... it was like they were hidden, anyways that freed up most of my space!!
Also if you noticed when you connected to itunes that it shows the data as other.... it should go down after you delete those files...
if its still large it might be voicemails as well... I'm going to try to delete some and see if that helps.
God Bless and good luck!!
Did you enable iTunes Match on your iPhone? If so, disable it by going to Settings > iTunes and App Store > iTunes Match > OFF
In addition, you can delete photos from any iDevice using copytrans manager without the need to sync/unsync with iTunes.