What is the ruling on studying and circulating medical images, drawings, and lecture content quoted from scientific books without referencing their original sources? Is this considered a legitimate form of quotation?

There is no need to investigate the sources of drawings and images, and the sin of transgression falls upon the الاستاذ (professor/teacher). One must beware of tanaṭṭuʿ, which is delving deep and searching into matters that do not concern one. Quoting and borrowing from the works of others is permissible with attribution, and the lack of attribution does not prevent students from benefiting. The استاذ (professor/teacher) can be advised by drawing his attention to observing academic integrity.