(Portland, OR)  --  An exhibit of works by the late Andy Warhol will open tomorrow at the Portland Art Museum.  Museum officials say the exhibit contains 250 Warhol prints and will be the "most comprehensive display of the Pop Art master's prints ever mounted."  The display will feature works including Warhol's iconic Campbell's Soup can and an image of Marilyn Monroe.  The exhibit, from the Collections of Jordan D. Schnitzer and His Family Foundation, will run through January 1st.