How does Dropbox “Overwrite if File Exists” work?

I have a shortcut that uploads a photo from my phone to a Dropbox directory and then creates a markdown link to it. It’s great.

But I just discovered that if I run it from a screenshot (without first saving it to my phone’s photo album), it is saved with the name “image.png” — and no doubt the next one will be too.

If “Overwrite if File Exists” is on, presumably it will overwrite. Does anyone know what happens if it isn’t on? Does the shortcut fail, or does it revert to Mac-like behavior and add a number to the end of the filename?

For some reason I’m messing up every attempt to test this (without losing actual data), so I’m hoping someone has figured this out already.

Thanks!

Ok, figured it out. Turning “Overwrite” off does indeed do the sensible thing and save the screenshot with a modified filename. I do have to wonder why so much is left undocumented.