I have photos on my iMac organized into folders. These may include images taken with my iPad, another iPad, or scanned from slides or prints, and may be edited on the Mac. When I sync my iPad, they currently appear in the From My Mac section of iOS Photos (the stupid interface seems to change with every major iOS update). However, I cannot figure out how to display them in the correct order on the iPad. Despite instructions from various online sources, dragging does not work. Why is this so hard?