Header Highlight Content won't display images

All I can get to display is the one long box on top...the 4 smaller featured content boxes below won't display the featured images...in fact, once I add a featured image to the page, the excerpt from the page disappears as well and I'm left with a grey box! I tried different sizes of images for the featured image, thinking it didn't like the sizes that I was uploading...to no avail. What am I doing wrong??