Hi Erilee,
Welcome to Auctiva! If you place your images in your listings using the "Select an Image" boxes on the Auctiva lister page, and images that are larger than 400 x 300 px will automatically be resized to about that size for optimal display in the template and will automatically have the "Click to Supersize" option.
If you place your images in the "Select an Image" boxes but the images are smaller than 400 x 300 px, the images will not be resized nor will they show the "Click to Supersize" option.
If you place your images directly in the description editor using the "Insert an Auctiva Hosted Image" button on the description editor toolbar, they will not be resize nor will they contain the "Click to Supersize" option regardless of image size. This button has an icon of a mountain/sun on it and it located directly to the left of the "User Links" menu.
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 of our site:
http://www.auctiva.com/help/requesthelp.aspx-Mike
