Can't import images into Scrivener

I have Windows 10 pc and am running Scrivener v. 1.9.7 but scrivener won’t let me import images into the Front Matter folder or anywhere else. It keeps showing this message:

Cannot import files from within current project

The set of files being imported contain files
that are within the current project folder.
These files will not be imported.

I have no images at all right now but I need to add some. How do I make this work?