Every entity has a subpage called “Assets” which contains miscellaneous content that is related to the entity.
The first asset type are Aliases, which can be used for search and mentions.
The second asset type are uploaded files to the entity. By default, an entity can have 3 files attached to it, generally an image, pdf, or image. Premium campaign can have 10 files attached to each entity.
Lastly, the third asset type are links. For example, if a character has a character sheet in DndBeyond, or you wish to attribute the image used on the entity, adding a link to that resource outside of Kanka will add the link in the entity’s profile sidebar.