Adding pictures of your products in Yahoo! Store is pretty easy. If you only have one or two images to add, you can simply do that through your standard Store Editor interface. Simply go to the product page that needs the picture, click, "Image" and upload your picture. However, if you have alot of product images to add to your Yahoo! Store, you will want to use the "Multiple Image Uploader"
1. Login to your Store Control Panel and click on "Store Editor."
2. Click "Controls" button.
3. Click the link, "Multiple Image Upload" (be sure to click "Read the Requirements" first).