People automatically use metaphors and analogies to compare and contrast ideas and information in their mind. Obviously visions or images are going to be used to help describe some of the concepts that are being compared. A concept might not need a vision; however, if it doesn't have a simple vision tied to it. For instance if you think of a person then the vision of a person might be connected; however your description of that persons personality - if they a nice or mean, smart of stupid - wouldn't have a simple vision tied to it because you are describing behavior. You might pull up various visions of them being nice or stupid in order to reinforce the concepts - however they are probably less tied to vision than concepts that are more simply visual.
Humans minds use schema to store complex sets of information or ideas. In this way understanding of the world can build and change when your current ideas and concepts are challenged by new information. Schema are not likely to change easily, however, as people are biased and more likely to notice things that fit into their currently held ones.
My guess would be that some schema are more unconscious and some are more accessible to consciousness - probably depending on what you were doing recently and if it related to some of the schema you hold. In this way your thinking can be influenced by the ideas that you learned and formed in your mind into schema.
Your unconscious mind holds many preconceived notions ('schema') and uses metaphors and analogies and visions all of the time. Depending on the circumstance different aspects of the world are going to be more accessible to consciousness. In this way the unconscious mind and conscious mind work together to help guide thoughts and feelings - depending on how unconscious a thought or feeling is helps to determine if it is logical, verbal, or easy to process (all of those are aspects of 'system 1' or the unconscious) or not.