Image Position

I have images ready for import and exported images from my site for some example products with images so I can develop a template. My images are in an external assets management program and are each identified by a filename, product code and an integer view code from 1 up to the number of images I have for a given product. “1” would be the main image while “2” and above would be additional images. This code pretty much corresponds to the image “position” field in CS-Cart. In building my import images CSV file I assume I should just use the view code for position, but I do have a question as to what position 0 means in CS-Cart. For example, if I have 4 images of a particular item with view codes 1 through 4 respectively, where 1 is the most important image and 2-4 are images of decreasing importance, should I just assign the most important image position 1 (CS pair type M) and the other images positions 2,3,4 (CS pair type A)? The position CS-Cart assigned all of them when manually uploaded is 0.