When you're reading a Japanese light novel or a web novel are you imagining cartoony anime style characters, or do you imagine them as real world people? I find it depends on what my experience with the story is. For example I'm more likely to imagine the story in a cartoony style if I've already seen the anime or manga, or if the author has a lot of illustrations available for reference. Kind of like how you're more likely to just picture the actor who played the character if you read a book after having already seen the movie. On the other hand if I'm reading blind and the only descriptor I have is the narrative. In that case I'll imagine the characters as though they were real people. There is an exception to this rule, and that is if the story has a visual aid, but it doesn't live up to my expectations. Like the narrative says a character is supposed to look one way, but the illustrations make them look different. Likewise if the art style just looks cheap or overly stylized, basically anything that ruins immersion. In these cases I will make a conscious effort to completely reject the offered visual aid, and either imagine something completely different, or if the error is small enough I will imagine a modified version.