Can you change the background image every n minutes when the filename never changes and it's the only image in the "wallpaper" directory?

[Chris Watson]

This may seem like an odd question, "Why would you want to do that?".

Here is why, many many mannnny moons ago I had a script that fetched the 
latest GOES full disk image of the earth every n minutes and used xv to 
update the root window so my desktop "wallpaper" would show the earth in 
full color and every new image would show it going from light to dark 
and dark to light with every new image I fetched from NASA as the day 
progressed. But alas xv can't be used with modern WM's to set the root 
window. Sooo....

Fast forward to today, and I miss that as my background

So I wrote another tiny script to fetch the latest full disc color image 
from nasa and store it in a new wallpaper directory where only that 
image is kept, no other wallpaper images. My script writes it out as 
"Earth.jpg". I have been trying to figure out how to get xfce to read 
that file every n minutes. But i cant seem to figure out how to get it 
to do that. The "Desktop settings" pane does allow to rotate background 
every so often but that only seems to work with multiple images in the 
folder. When you have only one image file, in this case a jpg, it wont 
re-read the file even if the file has changed contents as it's a single 
file. Is their any way to get xfce to re-read the same file every n 
minutes to set as the background?

Thank you!

Chris