For a photography portfolio site, I've created a plugin with custom post types that dashboard user will create gallery. From the custom-post-archive.php page, I'd like user to be able to click into a featured image and this would bring them to a page with the images from the gallery displayed in an order determined earlier by dashboard user and they will be displayed in certain divs with different specific classes. Think a scattered design layout of images/ divs of different sizes.
How do I break out the gallery images / array indexes in a loop that then puts the images in the divs with specific classes? The div classes will determine the "scattered" layout design which is a little more specifically placed than a masonry look. ( I've attached screenshot for a better idea of single post page.