Archiving a multimedia asset, either an image or video in LIGR is done by following the steps below:
Click on Multimedia in the left hand side dashboard.
Select Images or Videos depending on which asset you wish to archive. The below image is showing the Image section.
Click on the asset you wish to archive.
Hover over the image on the right of the screen and hit the Archive button, a green banner will appear at the top of the page to let you know that you asset has been successfully archived.