How can I add other repositories in the file picker?

An admin can enable additional repositories which then appear in the file picker.

1. To enable it Go to Settings > Site administration > Plugins > Repositories > Manage repositories.                                  
2.           
3.  Then click on the drop down menu besides the repository name which you want to enble and select "Enabled and visible".
4. Then configure the setting such as plugin name and save changes.