It would be very helpful for students if posters like these were posted either on the walls by the classroom library, or used in the library at each genre. Students would subtly learn what each genre consists of if they see these images everyday, and could eventually figure out what genre they enjoy reading most.
FREE Genre Labels for Your Classroom Library. This FREE document was designed to compliment my 43 page TEACHING GENRE KIT (which is available in my TPT store). It includes labels for your classroom library and features clipart by Thistlegirl Designs.
Classroom libraries need to contain a multitude of genres, topics, and themes. A core collection is key, but a revolving collection that matches a particular subject or theme should always be included.