I think the necessary information that might explain those images in the sutta passages above has been lost in the intervening 2,500 years. At least, I haven't been able to find explanations for them.
When I read those passages, I just take the obvious advice about cultivating dispassion towards, food, sense impressions, volition and consciousness. These are things that we ordinarily attach to, cling to, chase after and/or be enamored of, but they all bear the 3 marks of existence, so they are ultimately unsatisfactory.