How to create a "Gallery" post
Navigate through Admin > Posts > Add New.
Enter some title, click the "Add Media" button.
Click the "Create Gallery" button and mark the media images. Then in Gallery settings select the option (Columns, Navigation, Pagination & Thumbnail Size).
Note! You can set default settings from DivBlog admin panel and it will allow you not to set custom fields any time that you creating a gallery. You can also set custom styles for gallery types.
Just go to Post Formats > Gallery and set Default navigation type, Default pagination type and styles.
Don't forget to check Gallery format at right box.