You can add two kinds of references to presentations:
Document—When you add a document directly to a presentation, a reference to a unique document identifier is created in the presentation. The presentation can present the document from wherever it is located.
Folders—When you add a folder to a presentation, the folder reference is added directly to the Presentation Content, but documents in the folder are dynamically referenced. Documents added or removed from the folder are automatically added to or removed from presentations that reference the folder.