Building an online print shop I am trying to build an online print shop where user will upload their own images and select the size and quantity of the print they want and pay for the service.I want to use Drupal commerce for the backend. 

I don't know how to store the images. Should I store the images as single nodes, or files entities, or products, or something else so that I can easily added them to a product or to the shopping cart?

I have tried googling a solution or something similar, but I haven't get anything.


  The issue with the images is that the same image can be re-order
  multiple times without been uploaded multiple times and also the users
  can upload and delete any of their own images at any time.
I would either add an image field directly to the line item type and expose it to the Add to Cart form (along with any other pertinent fields) or figure out some sort of entity reference scenario with an Inline Entity Form on the line item to show the entity add form in the Add to Cart form. Might be a bit general, but googling any of those topics will turn up more info.