This applies to both creating a new post and editing an existing one.
To set the featured image of the post
select Format/Gallery > click Set featured image button > select Media Library
In the Media Library I can’t select multiple images for the gallery. So, I can’t create a gallery for the featured image of the post.
Thanks for your answer and providing such a great theme that is free to use. If you have time, could you please fix this issue?
Byoungil Choi