I’ve got you! Just a heads up, this is likely going to be spoiler heavy, but I’ll withhold as much as I can.
CG 1 (Bathroom) - Go to the library, and ask Sol to move from “your” seat twice
CG 2 (Sol’s bedroom[?]) - As far as I know, as long as you don’t kiss Crowe, this CG is automatic, as it’s incorporated into the natural flow of the story
CG 3 (Your bedroom) - Also as far as I know, you have to skip class and go to the movies for this CG to spawn
CG 4 (Sol and You) - Ensure that your affinity with Sol is high enough so that he can walk you home after the arcade; it should be a score of 8, at minimum, and you have to select the option to have him walk you home – you must go to the arcade. Just a reminder that the CGs will be different based on the genitalia you pick, so photos 1-4 of 8 OR 5 - 8 of 8 will be “missing” until you go back and replay the route with different genitalia selected.
Hope that this helps :) Let me know if you need clarification, or if it doesn’t work for you. I can tell you exactly what I did, so that you can get it for sure.