Images not showing full in slider (Magzimus Theme)

Hi.. I bought this theme yesterday and am having some difficulties with the slider. I can get it to work if I do not insert a “full URL ” under the box marked “Add to the Home Page silder” and delete the custom fields. The only problem then is that it picks up the small versions of photos I have inserted into the posts themselves and so the slider imagebar isn’t full and the images overlap each other.

When I try putting the full URL in and keep the Custom Fields it won’t even recognise the post in the slider.

http://www.rmfnation.com