In the documentation is mentioned that the display type can be:
Controls the appearance of the menu item. One of "MENU_ITEM", "TEXT", "BUTTON", "INPUT" or "INPUT_GROUP". Default is "MENU_ITEM".
But there is also available the type "IMAGE". I can not see how this should be configured (where to set the image you want to use.
Is this supported and if so how to ste this / is there an example?