Croma "Capital" Template: Unable to change Global Background

I’m brand new to Envato Elements. I downloaded the Wordpress Croma template, installed the Capital demo, and have been trying in vain for the last few hours to change the background image. First I removed the background image from the menu Croma|Look and Feel|Main Background, then when I tried to add my own image, the background on all the pages is now gray. I couldn´t even put the original image back. Sigh.

You should contact the author for support. He’d be the right person to help you.