I've moved this post to the Help section, where I think you'll get better attention. I hope this is OK.
However, if a photo on your iPad was added through a sync operation with your PC it cannot be deleted from the iPad. You have to remove it from your PC and then resynch. Only photos that were added to your iPad not through a synch - perhaps received as an email attachment - can be deleted on the iPad itself.
If you need to be able to do this, there are several third-party apps out there that have this capability.
Tim