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
This should work if it doesnt then your itunes fails.
To delete the photos off your iphone or ipod or watever simply do the following.
1. Open up itunes and click on your iphone/ipod.
2. Select the photos tab.
3. Where is has the ticked box "sync photos from" just click on the box again.
4. Itunes will ask if you want to remove all previously synced photos, Click delete!
Thats all it is. (WARNING!!! This gets rid of all photos)
If the photos were created on your iPad you can directly delete them on the iPad. If the photos were synched from your computer and you can't delete them on the iPad. You have to sync with iTunes on computer. In additon, if you have not installed iTunes and felt it hard to use, you can attempt to delete all photos on your iPad.