Can't have the header image to work in Gridmarket

I have a multisite with MarketPress and FrameMarket with the child theme Gridmarket.

I have moved the gridmarket theme to the same level as FramMarket and deleted the gridmarket in it's first place.

I have downloaded the New Blog Template to be able to make a shop template for my site - becoming an etsy like site...

I have added a new site which I gave a template name and then started to design it. Most things looks correct but I can't get the header image to shop up.

Uploading the image worked perfect - go the crop question an then everything looks good.

But.... the image does not show up!!

I have read around on older questions with describing image downloads wich does not work.....

I can't understand what I'm missing out on - can you please help me out. Keep it simple because I can't coding myself.

Kind regards,