Does one violate a prohibition if sees pritzus, immodesty in a CGI, comic books and in handwritten drawing or does it only apply to real pictures?
Iggros Moshe Even Haezer 1:69 applies the prohibition of seeing immodestly dressed women/men to seeing inappropriate behavior, with the reasoning that the problem is the thought process it instigates. Based on this logic he applies it to images in films, and even reading about inappropriate activity in books. So if these drawn images conjure up inappropriate thought processes, then the fact that you aren't looking at an actual human form doesn't matter, any more than that when you are reading a book you aren't looking at an actual human form, and yet the prohibition applies.
ובדברי חשק יש עוד איסור אפילו כתובים בלשון הקודש שמגרה יצר הרע בעצמו ומי שחיברן ומי שהעתיקן ואין צריך לומר המדפיסן הם בכלל מחטיאי הרבים
In arousing literature there is another prohibition [besides issues of reading them on Shabbos] even if they are written in Hebrew [which may have been a mitigating factor vis-a-vis Shabbos] that they arouse the evil inclination in himself. One who writes them, transcribes them and certainly one who prints them are among those who make the public sin.
So if such an issue exists in words, pictures wouldn't be any more lenient.