How to add single image in Shopper Press – Responsive Theme?

Hi, I am new to responsive theme and trying to understand it. I have installed the theme and restored demo products.

I saw a video tutorial for adding gallery but for gallery, it works when I have more than one product images.

How can I add one image per product and that image should be displayed in place of gallery images. I tried to add both shortcodes [IMAGES] & [IMAGE], so either would work but still when I have single image, it does not show.

Yes, it inserts in the description but does not show on the correct place, where it should be displayed.

Any clue, tip or help would be highly appreciated.

Thanks in advance.