Hi schmidt9331,
Thanks for checking with us on this. You actually can update the captions on your images in bulk provided that the images you'd like to update the captions for can be made to appear on the same page of the Manage Images section within your account.
When you are in the Manage Images section of your account, you can update multiple captions at once by updating the "Caption" fields next to the desired images and then clicking the "Update Captions" button once when you are done.
If you have any additional questions or concerns, please feel free to contact our customer support team using the web form on the following page:
http://www.auctiva.com/help/requesthelp.aspx-Mike