The frame was from a modern wooden version i saw a while back.  You need to print 4 of each piece.  No support need in print.  Connect 2 front pieces together using the support piece.  Connect 2 back pieces together using the support piece.  that will give you 2  300mm long frame edge.  sandwich you picture/photo/whatever between the 2 and use an M3 flat head screw in each of the 4 holes.  The countersink for the flat head screws will be facing the back of the object.  the weigh, which is minimal at 12% infill is enough to provide a pull on the object.  I would like to make the frame edges a little bigger and 3D print screws for this so it is all 3D Printed.  Feel free to remix.