Add an image to the code

Hello.

I need to add the following image (screenshot4) to the Marketpress code as it is awkward that my buyers do not know what kind of payment options they have until AFTER entering shipping info.

However I am having a hard time finding where exactly this is found in the source code. I am attaching a firebug screen shot (screenshot3) to show exactly where I want the image to be inserted.

What file (php or html) is this located?