Attached are 2 images of the results that I'm seeing.

Okay, I think I figured out what it is - it appears to be a donation ask from Mozilla, which makes sense if you have just the regular Mozilla start page. However, since I have the new tab homepage ad-on enabled it didn't make any sense.

Start Firefox in Safe Mode {web Link} by holding down the <Shift>
(Mac=Options) key, and then starting Firefox. A small dialog should appear. Click Start In Safe Mode (not Refresh).

Is the problem still there?

mccdrew said

Okay, I think I figured out what it is - it appears to be a donation ask from Mozilla, which makes sense if you have just the regular Mozilla start page. However, since I have the new tab homepage ad-on enabled it didn't make any sense.

Your extensions list shows "Homepage New Tab 1.0.8.1" which has been removed from the Add-ons site, but according to an old version of the page from Google cache:

Merges the new tab speed dial with the homepage that you see at about:home.

So it may be normal for the page to retain the background of the built-in about:home page even as it displays content from the about:newtab page.

If you just want to show the about:newtab page as your home page (without merging the two together), you could disable the extension and set the home page address to about:newtab instead.

And/or, if you want to remove the donation background, hover the text of the message to reveal a little "x" button. See attached screenshot.

Source: http://forums.mozillazine.org/viewtopic.php?p=14726177#p14726177