Your Media Library is where you can store any files, images and articles that you frequently use in your emails. This content is stored in your account, so that it's easily accessible when you wish to reuse it.
To Move Content in the Media Library
In the Comms area of your account, select Media Library from the menu on the left.
Select the file(s) using the checkbox and click Move.
Choose the destination Library, and click Move.
The item will be moved to the destination folder.