how do i transfer pictures from my computer to my ipad
When I sync my IPAD to my computer I do not know how to add another directory to the list of directories that are available.
iPad 2, Windows 7
To sync them to the iPad's Photos app your photo folders will need to be directly under the same parent folder, as you need to sync all the photos that you want on the iPad together in one go as only the most recent photo sync remains on the iPad - synced photos can't be deleted directly on the iPad, instead they are deleted by not including them in the next photo sync.
Syncing photos : http://support.apple.com/kb/HT4236
If you want more flexibility that what is currently possible with the Photos app then you could consider getting and using a third-party photo management app instead e.g. Photo Manager Pro.