Update background images on file change

Good day.
I really like an ability to set custom image as explorer background. I have made a script that outputs my current wallpaper to a file each time it changes, and set it as my background.
However whenever this file changes the background stays the same unless I close and reopen the window.
Would it be much trouble to make it so that the background updates whenever the file it's set to changes?
Also, could you please add a tiled image mode that aligns to center of the window as opposed to upper left corner?
Thanks for your time.