Sometimes I might have to do a lot of editing because there may not be enough natural light coming my way. Every picture gets edited in some way (plus my camera tends to lean towards a blue hue.) I'm not aware of any rules with photo editing, but I'm not sure why you would be changing a photo so much that your item wouldn't look the same. That's not really the point in editing a photo. Ideally you want the item in the photo to match what the customer will receive. I think the only repercussion is possible bad feedback if the customer doesn't feel that the photos 100% represented the item he or she ordered.