Feature Slider image

I am loving the theme, but having problems with trying to figure out how to use the feature slider. I have looked through some of the other support responses and I *think* I am doing all the right things. I have tried linking the image from another site outside of my host page, it didn't seem to work. I have tried just using a smaller image size. I did make sure that I have added the image as "Featured Image" in the post and when in the Theme Options added the URL of the page, I think that is correct? I didn't see where to simply put the Page ID, just the URL. So I am not sure what I am missing? I have only one post on there public, one private because I am just trying to get a banner (logo banner) to be within the feature slide. Does that make sense? Here is the site www.cakecooksglutenfree.com THanks in advance for the help.