A media handling system is provided for an imaging system, such as an external drum platesetter. An edge clamp used to secure a printing plate onto a cylindrical media support surface of the external drum is movable about the drum surface to accommodate the use of different size plates. The edge clamp includes a clamping bar which is radially movable with respect to the media support surface to attach to the media support surface and capture an edge of the printing plate by employing vacuum hold down force.