Where are Product Images Saved?

Maybe I’m missing the obvious, but three questions to help understand this:

  1. Where are product images saved? In admin, when I add a product and upload from local, where does it save it and what is it called?

  2. Is there a rule somewhere, or CAN there be a rule somewhere that says all thumbnail pictures are found in this folder and all detail pictures are found in this folder with the format of PRODUCTCODE.jpg?

  3. For bulk image uploading, must I always do a .csv import telling CS-Cart what the product ID is and where the image paths are located. Seems odd to always have to do that.