Yes, there’s a difference between a cover image and a featured image.
A cover image is a wide image used as a cover of a new web-page or blog section. It can be used when you start a new article section or story. It’s also possible to add text and color overlay. This will make your article more engaging and will help your readers understand where a new section of the article starts.
A featured image is also called a thumbnail image. This is considered to be the main picture representing the content on single posts, blog archive web-pages, homepage, social media feed (when the article is being shared), etc. The featured image is created to give the information to the reader by just a quick glance at it. Its position is controlled by your WordPress theme.