You can choose a post format for each post. This will add the correct icon on the blog posts list and also will show you additional options.
The Post Format selector appear on the Document right panel
Appearance → Customize → Blog → Single Post with the option Featured Media Position
These 3 options will appear in the front end this way:
This option shows the featured image on top of the post with parallax effect.
You only need to add the featured image using the default WordPress method:
Regular Header + Featured Image
This option shows a regular header with the featured image under the title.
Regular – No Featured
With this option the Featured Image is not displayed automatically on the single post. Instead, you are free to add any custom content.
WordPress Gallery Lightbox
You can open the default WordPress galleries in a lightbox by enabling a single option.
Go to Appearance → Customize → General → General Settings and activate the option WordPress Gallery – Lightbox
You can use a single featured image (WordPress feature) or create a gallery of featured images.
See Blog – Featured Images/Video to learn how to setup your featured media.