Within campaigns there are often resources that the GM will have to show players at various points, such as notes written by NPCs to further the plot or maps of areas etc. Although it is possible to add these into the chat section they are often lost after a few messages occur and they are then scrolled into oblivion.
Have another section within the campaign page where the GM can add new images like a small gallery to allow the users to view any of the information related to the campaign without having to trawl through chat logs.
This should ideally allow you to give the artifact a name, a description and a url so that users can see tooltips as to what the artifact pertains to and click on it to load a new window/tab showing the content, much like the common image embedding functionality.
This has now been added so all GMs can add and remove artifacts from their campaigns.