I haven't made any major changes to my website, other

I haven't made any major changes to my website, other than adding posts ... definitely no theme changes. A few days ago, the banner across the top of the page disappeared. I haven't made any changes to the site in a month or so. It just stopped working.

It's been a while since I set up this site and I can't remember where this image is placed.

The website is: http://www.unitedcreditunion.org/

The white area above the menu is supposed to have a graphic.

I have an update due for Wordpress but I didn't want to update it until I had this issue fixed.

Thanks