My proposition is to place "move backward" and "move forward" buttons in some fixed position on page instead of keeping them on each photo. with current solution, to move photo you have to look for these buttons, move mouse to new location of picture, again look for buton, again move mouse… and so on. It would be much easier to keep mouse in one place (where buttons are located) and just observe how grid changes when photos are being moved. Moving multiple photos would also be a big benefit!