The Media Panel can help you find media to add to the LUNA Workspace.
Open the Media Panel by clicking on its tab near the bottom of the browser window. Close, or minimize, the panel by clicking on the tab again, or the “x” box in the upper right corner.
You must be logged-in in order to select a Media Group to find images from. Once logged in you can use the Select Media Group pull down menu to open a Media Group and then simply drag and drop media from the Media Group into the LUNA Workspace. (Only image files from your Media Group will appear, all other file types will not be supported in a presentation and so are not visible in the Media Panel.)
If you want to add media to the LUNA Workspace that has not been added to a Media Group use the search feature. Your results will depend on which collections you've selected and how many objects you've chosen to display per page.