Background image won’t change

I have an animated GIF as my front page image at Church of Zero. The file that displays MUST be named Space2.gif, then it shows up. But when I select a different image via Background image, it will not update (BG Image shows the new gif, the screen does not, and insists on displaying “Space2.gif” – the filename is somehow locked into the first flexslider slot and i don’t know how to get rid of it. I can rename another file to Space2.gif, and it shows up. But I can’t remove the filename and use Space5.gif, or add the video plugin to display space2.mpg (which is 1/3 the size.)

iv class="header_container home ">
<div class="slider-container">
<div class="slider-wrapper">
<div class="flexslider">
<ul class="slides">
<li>
<a href="https://www.churchofzero.com/?page_id=75">
<img alt="Slide Image 1" src="https://www.churchofzero.com/wp-content/uploads/Space2.gif" style="width: 1039px; height: 494px;">
</a>
<div class="flex-caption-wrapper">
</li>

Any ideas appreciated, thanks.