Returning images through AWS API Gateway

I'm trying to use AWS API Gateway as a proxy in front of an image service. I'm able to get the image to come through but it gets displayed as a big chunk of ASCII because Content-Type is getting set to "application/json".

Is there a way to tell the gateway NOT to change the source Content-Type at all?

I just want "image/jpeg", "image/png", etc. to come through.