At the free level (which is my assumption, based on your lack of a tag to the contrary), you can share in one game at a time. You could switch that game at any time, and the people from the previous would just lose compendium access for the duration. It would be an inconvenience, but you could juggle it that way. If you are running from a module, all of the modules resource (maps, monsters, etc) can be used in as many games as you care to create. Art libraries represent account-level purchases and are not shared. You can place the assets on pages and make them selectable by players, but they cannot do the things with them that you can as the owner (copy and paste between pages, for example). But if you bought a token pack, you could place all of the images on a token page as a "browsing area" for players. You could also place them in handouts and share the handouts, with similar restrictions.
