This is post #7 of 31 in the challenge Mastering WooCommerce
If you have want to change product image sizes for all WooCommerce products, you can go to WooCommerce > Settings > Products Tab, and go to “Product Image Sizes” section.
Last step will be downloading a new plugin called ‘Regenerate Thumbails‘.
Download the plugin and install on your site. Then you can go to Tools > Regen. Thumbnails, and click to regenerate all the thumbnails with new sizes easily.