Only a small percentage of DVDs make use of this, e.g. Me,Myself & Irene R1, Southern Comfort R1, Betty Blue R4, Memento SE R1.
Believe me - once you see a few jacket pictures, the novelty quickly wears off

It's really not worth making it a priority. Although I must admit, I really love the Memento jacket picture
(Not a Tosh but my Sony DVP-NS300 shows jacket pictures btw.

)