Images not displayed in category
My apologies, there seems to be a slight bit of a misunderstanding/confusion of what the Category content image is actually used for in the XF2 version of AMS.
The Category content image is specifically designed for and is only used as, a backup Cover Image for Articles when using (List View, Grid View, Tile View layouts) for Articles that do not have a Cover Image set for that Article. That is its primary function and designed intended purpose. There are currently no secondary usages within AMS 2.1.x.
The Category content image was not added to AMS for the purpose of displaying it on Category Pages (even tho I can understand and appreciate that some people might want to do something like that, which can be easily accomplished via customization of the Category View template).
Note: AMS 1.x did have some unsupported experimental secondary usage of Category Images in the form of a basic Category Navigation block, however, none of the non supported experimental stuff was carried over to AMS 2.x.
I'll post a how to (when I have time) on how to add a sidebar block to the Category Page that will display the Category content image if a Category Content Image is set for the Category. This should help you in making some customization to the category page if you want to
Note: You are more than welcome to make a suggestions for secondary usages for the Category content image (like an option to display a Block in the sidebar to display the Category content image). I've implemented 1000's of user suggestions. Just make sure you provide details (with mock-ups since this would be a display type suggestion).
Example, there is an existing suggestion posted by a Premium license holder for creating a Widget Definition to create Category Navigation Blocks for RMS that would include using the Category Content Image as part of the block. He included a mock-up of what he wants. If implemented, I'd implement this for AMS, UBS and Showcase as well.
Again, my apologies for the confusion/misunderstanding. I hope you understand the purpose of the Category content image and that its not designed (or intended) to be displayed on the Category View template.