Hi i hope i can help with my little knowledge:
1. Connect your ipad to itunes.
2. Then drag the pictures from your pc to your itunes at the left side under librar column, you cannotice if it is acceptable if you can see + sign highlighted.
3. Then click your account (like your ipad name) then search the photos tab.
4. Under photo tab check the box beside sync photos.
5. Then after that at the bottom youcan see Sync then click.. And thats it ( sorry english is not my mother toungue).
I find that on the internet http://www.***/how-to-transfer-photo-pictures-from-ipad-to-pc.html,which similar to your ways and help me solve my problem,thanks.