Change Spirit Hero, Header image?

Okay, I know this is stupid, but I'm new to Upfront. I've watched the videos, read the pdf, but I can't change the hero/header image in Spirit. You know, the one with the ladies on the beach (all pixelated). I've been at this for two hours. Help!

When I select the pencil edit button in the upper right hand corner, a text block appears "Finish editing background". There are no handles, no edit box, no way to edit or replace the beach ladies image. In fact it is not there.

Thanks!
Chuck S.