The "Documents" menu on your Organization Management Page has a number of options:
Documents: A number of document types that can be used to populate your page.
Document Files: Storage for any pdf or docx files that you wish to store or get a URL to link elsewhere.
Photos: Upload pictures here that you'd like to show in a gallery on your org page.
Images: Upload any images here to get linkable URLs to embed the images elsewhere. Also great for storage.
Logos: One upload here at a time will replace your current organization logo.