Here is the artwork to the soundtrack of Mac & Devin Go To High School, which is due out on December 13th (the album). Not sure about the film though...
If interested, here is the schedule to their 6 city tour that they will be participating in for the soundtrack/film.
Dec. 5 - New York, NY Terminal 5
Dec. 6 - Philadelphia, PA Electric Factory
Dec. 7 - Washington, D.C. 9:30 Club
Dec. 10 - Atlanta, GA Tabernacle
Dec.12 - San Francisco, CA The Warfield Theatre
Dec. 13 - Los Angeles, CA The Wiltern