First, plug your iPad into your computer using the syncing cable.
Then, open up iTunes and select your iPad from the 'Devices' section on the left hand side. A summary of you iPad should open up in the main window.
At the top, select the 'Photos' button. Then, check the "Sync Photos from..." box.
Once you click "Choose folder" option in the drop menu, you can then select which picture folder to want to transfer onto your iPad.
Finally, click Apply at the bottom of the screen.
Hope that helps!