Make amends to donate.tpo page for mystery swag campaign

I'm filing this ticket to make amends to the header image(s) for the mystery swag campaign on the donate page.

• Smaller height for bg image @nicob - once I provide this to you @kez, will it be possible for the bg image to span the entire width of the page, so there's no black borders?
• Add padding/white space around foreground image @nicob
• Determine breaking points for different sized foreground images @nicob

Thank you @kez!!