There're two types of Geometrical Assets right now:
A Geometry in this context is an abstract entity, for which in the section Files an arbitrary number of real files can be provided. Such files can have different resolutions and/or formats but should be identical concerning to origin, dimensions, etc.
In this page, you may create and delete Geometries. You can also edit their descriptions. However, after a Geometry was created, its Name cannot be changed later on.
Finding and replacing of Geometries and Layers is available in Assets/Geometries/Search.