I want to display the count of files when the Details view is active. I've tried looking through the list of details that I can add, but have had no luck.
I think what we're looking for is a display of a folder's properties in the details pane when you click on it, as opposed to when you actually open the folder. And that doesn't seem to exist. There used to be add-ons that would show the folder size in a column...
Open Windows explorer, go to > Organize > Layout > tick Details Pane
Now you will see at the bottom of the window the number of items when you have selected a folder, and additional properties when you select a file like a jpg file.
Items includes everything in the folder including other folders. If you select some of the files in a folder it will give you that selection count.