Setup Product Image Sizes

WooCommerce > Settings > Products > Display

On bottom of this page, please make sure Catalog Images and Product Thumbnails have image sizes setup as:

• Catalog - 280px width and 180px height,
• Single Product - 350px width and 350px** height,
• Product Thumbnail - 80px width and 80px** height

To know how to add product images and gallery, please checkout official documentation here: http://docs.woothemes.com/document/adding-product-images-and-galleries/