I added files into the media library in email marketing, why are they not showing in my website media library?

The Media Library synchronization function is a one way street. The sync occurs from the E3 Media Library to the Email Marketing Media Library, but not the other way around. 

Files uploaded into the E3 Media Library will appear in the Email Marketing Media Library. However, if a file is uploaded to the Email Marketing Media Library only it will not appear in the E3 Media Library.