If you have images attached to auctions in the file you want to import to Pro, you will need this field. The images of course will have to be uploaded to Pro separately, but the image field tells it what image is attached to what auction. In your Excel file you would have columns for each field -- you can have image columns there. For example you can have Image 1, Image 2, Image 3, and so forth. When you do the batch import you can match the images field up with each image column in your file.
I hope this is not too confusing, it is easier to understand once you are doing the batch importing and you see how the fields match up.
