Did you check out this post of mine?
I’m using it to randomly generate avatar images for users until they upload their own. To do this, I’m creating a template column that merges the URL schema and their email address to generate a unique avatar. I’m then using an if then column In the data editor to show the randomly generated template if the image column is empty. If it’s not empty (meaning that the user uploaded their image) then I display the image.
If you scroll down to the bottom of the post linked above, you’ll see what the end result is!