When I select A4 as the paper size to print photos, my Canon pixma MG2450 doesn't recognise this as an appropriate paper size. It keeps saying "media type and paper size not set correctly". It regularly prints out documents using A4 paper. Is there some other adjustment somewhere in the system?
Please mention the steps you are following. For reference you can add more brief steps while printing like paper size, print size, size of paper you are putting into the printer.
Also, mention the OS, PSE version on which you are facing the problem.