Can I associate multiple images with my listing when I list using the AddItem call?
Certainly. You have 2 options
eBay Hosted Images - If you choose this option, you will have to upload picture files to the eBay site (using eBay Picture Services (EPS)) . This can be done via the UploadSiteHostedPictures API call. Generally one to twelve pictures may be used for the item. Specify the EPS URLs in the PictureURL tag of the AddItem call.
Self (Vendor) Hosted Images - The image is stored on a site of the seller's choice. Currently we allow only a single self hosted image with a listing. Specify your image URL in the PictureURL tag of the AddItem call. To display more than one self-hosted picture on eBay, you'll need to use HTML in your listing description and specify the additional images in the description. To make your listing appear quickly enough, the file size for your picture should be under 50 KB.