Go to a mirror. Point at your image. You are pointing at one tool capable of testing any tool on a manual basis. On an automated functional testing tool basis you would need a tool which fulfills the three core functional areas of an automated test tool with your application: Can it Identify an object? Can it Operate an object? Can it validate the state/attributes or an object?
OK, now the bigger question? Let's say you do find what you believe is a functional defect, if you do not work for the software vendor, Adobe in this case for photoshop, how will you be able to confirm that your test does or does not effectively address a functional requirement?