providing feedback based on subject response

I’m having trouble trying to figure out how to provide feedback based on subject responses. What I’d like to do is present two pictures (left and right), then have the subject select one of them (e.g., left) and have only their choice stay on the screen for a few seconds (e.g, the left stimulus stays on the screen by itself for a few seconds and the right one is not displayed). Then I’d like to provide them with feedback about whether or not their response was correct. Is there an easy way to have the display change based on the subject’s response and then provide feedback based on that same response?