With a return by Paul McCartney on tap this summer at Miller Park, the arrival of "Rockshow," is well-timed. The film, which screens at the Bayshore iPic at 8 p.m. on Thursday, May 16, and at 2 p.m. on Sunday, May 19, was filmed on the same 1975-76 U.S. tour that led to Paul McCartney & Wings' triple-live album, "Wings Over America."