Specific changes made in "Customize" not showing up on page

Hi all,

I’m using the Sequel theme and the Fourteen Extended plugin to try and make a site. The problem I keep running into is with the full-page slider. I can turn it on, but images don’t fit. They always display the same size with a grey border on the right and bottom.

I can fix the problem by tweaking some settings in Appearance-Customize, and in the preview pane the slider looks fine. I can also change its dimensions, etc. and all of those changes also are reflected in the preview pane. None of them show up on the actual page though. No matter what settings I change, on the page itself the slider remains the same.

Has anyone seen this before? Any thoughts? You can see the page in progress at https://www.thingsdangerous.com.

Thank you!!