Interesting... Here is an article about people with a condition that makes them unable to produce mental images.
Aphantasia: A life without mental images http://www.bbc.com/news/health-34039054
What I've found in my process is that in my past, almost 100% of the reason I would spend so much time in pictures / imaginations in my head, is to escape reality / distract myself from the things in this world / in my life that I don't understand / don't like / struggle with -- you know the day to day reality of money, suffering, struggle, frustrations, conflicts, a screwed up world -- where I'd take information that I liked the sound of -- in my case it was things like spiritual beliefs / stories and turn it into pictures in my head, dreaming up alternate realities to keep myself stimulated / enabling myself to 'explain' things in a way that makes me feel good, and to see myself as some character with a purpose / reason for existing that is based on / dependent on pictures / an alternate reality in my head that makes me feel better about things -- when in fact I'm not actually practically investigating reality / relationships / the mind / the world system to understand the problems and explore practical solutions to create a world / humanity that is worth existing in and with.
I mean, I can use pictures in my head practically - to assist with conceptualizing certain things -- but now the difference is that I'm not using it as entertainment / an alternate reality. What I've found is that, the more I'm learning to Live in practical reality, living without belief systems, standing within and as the simplicity of - 'I am Life as all as one as equal' - is that I don't have the desire to sit and daydream and picture all kinds of stuff in my head - because I'm busy living and developing my self expression, skills, and purpose as a physical life lived with the purpose and self commitment of assisting and supporting to bring about solutions to create a world that's best for everyone.
This kind of condition of not being able to produce mental images raises some interesting questions in relation to belief systems / personalities that depend on pictures in the head in order to maintain one's purpose / stability / experience of one's self -- who would you be, what would you do - if all of a sudden, you could not produce any images / pictures in your head?