Well Arcade doesnt use box - front, it uses advertisement flyers, so if you dont have those checked under your box - front priorities then you wont see them. This is why the priorities are there in the first place, you can add/remove as well as reorder them as you see fit. I cant tell you what to select for your specific build, check the image types you want per image type, in the order that you would like to see them. It's quite straight forward, only want to see box front or flyers for arcade and nothing else where a box is supposed to show, then just check those two image types under the Box - Front image priorities and anywhere a box is shown only those two image types will be shown. Same for screenshot priorities, uncheck anything that isnt a screenshot and arrange the remaining screenshot types in the order of your preference.