We are visual writers - "show it and don't tell it". In some schools of thought the screenplay is just a blueprint that is fleshed out by the director and the production and post production units. Here the visual structure (space, line, shape, tone, color, movement and rhythm) is woven into the story structure by a director who has studied the script in deep detail and visualized their version of the story within the words written. But there is no harm in the writer's use of these components in the script. It's like with everything else in our business - less is more, so manage your visual queues or symbols mindfully. Be mindful of not falling into the stereotype pitfalls associated with these visual queues, and above everything weave them into the writing skillfully and not "on the nose".
Jijenji gave some great examples above of how visual components can create an additional unmanned character (e.g., death) in the cast. Another example is Speillberg's use of camera angles and ominous music to symbolize or communicate the arrival of you know who in JAWS (though I have never read the script for JAWS and I am not sure if that is a credit to the writer or the director - still a writer could have done that too). Sometimes the audience gets it and your story is analyzed and/or scrutinized well after your job is done and sometimes, like the best planned out set-piece, it gets missed. Still not a bad idea to use the visual components/symbols in your writing. Moderation is the key.