What would be the best way to make large amounts of similar collectible objects (+600)?

I'm starting a project involving digging into a 2d ground space to find objects. I'm not too worried about the layering system for the ground, but I'm going to have about 600 pictures of things to find. Instead of making 600 prefabs and hardcoding them in, what would be the best way to make 'prefabs of prefabs'? I want to be able to change the code of all objects if need be easily, while still allowing them to have their own independent image and values associated with them. What would be the easiest way to do this? All the images are numbered, so can't unity load them in itself?