This is a fix where you click on "cusomize page" on the main page, and two header images show.

Change the header code in both the general.html, and dndindex.html to the code below. One of the pages didn't have the <div class="ow_header"> tag at the front. It just started with the {if isset line. There were also tags out of place. I borrowed this from another theme that wasn't displaing the issue. 

<div class="ow_header">
  {if isset($imageControlValues.headerImage.src)}
  <imgclass="ow_header_img"src="{$imageControlValues.headerImage.src}" />
 {else}
  <div class="ow_header_pic"><img class="ow_header_img"src="{$themeImagesUrl}header.jpg" /></div>
   {/if}
</div>

Here is the css for the default header. Notice it has a height set, as well as a few other settings.
.ow_header_pic {
    background-image: url("images/header.jpg");
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
    height: 300px;
}
This is the css that is used when a header is changed. It will need to have a height setting to display correctly.
.ow_header_img {
    width: 100%;
}

Here is what I changed it to so the header_img will follow the same attributes of the default header_pic
.ow_header_img {
    width: 100%;
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
    height: 300px;
}

With these changes everyting now works fine. Well. except for the menu links pulling down when you customize the main page, but that's a separate issue. It was doing that before this fix.