Works are created as another custom post type called Testimonials. It has Categories that can be ordered as needed. Here you create just single post.
You can add an Image, Title and Category(es) for each Work post.
So basically, you create an individual post describing for each work in your Cases archive. After that you go to the Works > Add new.
On the new page you should insert Our Works shortcode from Visual Composer.
After that you can have options go make your works view Grid (by default) or Grid with filters and select Columns and Image size: