A Photo Set store listing is the best way to sell a set of themed photos on MV! You can use whatever theme you like, so get creative!
When selling a Photo Set, you'll want to first create a store item as you normally would. Once you have gotten to the "Select a Category" section, you'll want to make sure to select "Photo Set" as this will give you the option to upload a .zip file containing all the photos so the purchasing member can download them immediately upon purchase.
You'll also want to make sure to set the "quantity" of the item to 999 so it doesn't go out of stock (unless you want it to be a limited amount). Set your title and description, and when you've added all the fine details, make sure to hit save at the bottom!
When a member purchases a Photo Set, they can download it immediately (assuming you have added the images in a .zip file) by going to their Purchase History, locating the purchase, hitting the 3-dots to the right of the purchase and hitting "Download".