Hi @RCT,

In our festival booth, we use Square Register differently for two broad groups of products.
#1. Books and recordings we sell all year (including online): we set up each unique SKU as an "Item" in Square Register. This is a small number of products.
#2. Art banners that vary year by year and come in many styles and sizes (and are not sold online): we set up a single Item (one SKU) without a price. Then when we ring up a banner sale, Register prompts us to enter the price.
At the end of the festival, sales reports show us how much of each Item (SKU) we sold. For the banners, this is a single quantity: because we set up a single item, there is no breakdown at the size/style product level. We're okay with that, because we only need to know the overall quantity and total sales proceeds (from banners).

You could go with either approach. If I were selling many different photographs (and had a limited quantity of each image), I would be inclined to set up Register initially with an item called "Photo" or "Limited Edition Photo" and omit the price. As with #2 above, when I sold a photo, I would then select the Photo Item and enter the price for the specific photo selected by the customer.
This is a simpler approach, and you could always switch to #1 (individual SKUs for every unique Item) later if you find that #2 doesn't give you what you need in terms of reporting or inventory management.

Note: if you plan to sell your photos using Square's Online Store, and you want customers to be able to select a specific image and have the Square online store charge them the appropriate amount, you will definitely need to create an Item (SKU) in Register for each photo that will be sold online. (Just mentioning this in case it helps you decide between #1 and #2).