Hi Jerry,
If you are on the Unlimited Plan or the Premium Plan and you exceed the 1 GB image hosting allowance in a given month, you will incur an additional charge of $9.95 for each extra 500 MB increment that is necessary to support your peak usage. The current cap on additional image hosting charges on these plans is $29.85 per month.
If you have any other questions about your Auctiva account, please feel free to contact our customer support team using the form on the following page of our site:
http://www.auctiva.com/help/requesthelp.aspx#-Mike