You can't use the wild card operator in your example but this can be done if:
The folder is inside your documents folder. or
With a plug in that can list folder contents ( there are a number out there that can do this ), the folder can be placed anywhere.
You can also use Import Records | Folder to import all picture files located in a specific folder so you might be able to use that method. That's a trick I use to pull pictures taken from cameras equipped with eyeFi SD cards (that upload via WiFi to a specific shared folder) into one of the Databases I currently administer.
I created a new table and a script to import all the files from the folder, then I could get only the ".png" I wanted. =) Thank you very much!