Removing "motorcycle" image from Turbo design

I'm trying to convert my current SmugMug Pro site to one of the new designs and have spent hours trying to solve something really basic.

I selected the "Turbo" design, which includes an example picture of a motorcycle rider. I would like to replace the photo of the motorcycle rider with one of my own, but I can't figure out how to GET RID of that pre-populated motorcycle picture. I've figured out how to add a content block with a photo on top of it, but the photo I'm using doesn't stretch quite as wide so the motorcycle photo actually sticks out from the edges and is visible in the background.

Anyone know how to either delete or replace that pre-populated photo on the Turbo design? I'm guessing it's simple but I'm just not figuring it out.:dunno

Thanks!
Dale