Make sure to save the collection. Go back to the main admin page then refresh your website. It does take a few seconds to show the backend edits to the front end
Thank you for the screenshots! We have been seeing some issues today with theme assets not loading properly so I recommend reaching out to our authenticated support channels to report this and see if it is related. To access our authenticated support, please follow this link: Shopify Help Center.
Does this issue with the images happen in a different browser or on a different device?