We've added the option to upload several product images for use on your B2B store. Those using the B2B store feature will find an "Additional B2B images..." option in the More drop-down on product details pages. From this page you can upload product images specifically for your B2B store. You can also specify image captions and reorder images accordingly.
We've added image zoom functionality to the B2B store buyer interface so buyers will be able to click any product image thumbnail to view the full resolution version.