slide size is not matching the size of header

I’m trying to use a slide show instead of a header image. So I started a ‘new’ slide show with height at 250 and width at 1200px. The slide were uploaded from the Wpress gallery and are showing like thumbnails.(I already have a slide show on my right sidebar.) What am I doing wrong?

You can view my site as http://www.coutureandcannolicafe.com
Thanks!

https://wordpress.org/plugins/meteor-slides/