The right panel includes a Files and Links tab:
It has three sub-tabs, Media, Files, and Links.
The Media tab includes media files (image and video) added to messages or to the Files tab. All media files also appear in the Files tab.
The Files tab includes all files uploaded to the channel, the attachments folder (the default folder for message attachments) , and folders that you add.
The Links tab includes all links that you copy into messages.