The first image displayed on a product’s Media tab is used as the primary image for the product on your store. The remaining images are displayed on the product details page in the order they appear on the Media tab.
To reorder images:
On the Catalog tab, open the product whose images you want to reorder. Click the Media tab.
To make an image the primary image for the product, do either of the following:
Drag the image to beginning of the list.
Hover over the image and click the star icon when it appears.
