Product Images

If you use WooCommerce 3.3.x then use WordPress Customizer (it’s a feature in the WordPress admin) to change the catalog and single product Image settings.

Go to Appearance > Customize > WooCommerce > Product Images.

To change product widget image size go to Settings > Media > Thumbnails Size.

More information about product image settings you can find in WooCommerce Documentation.

Note:

After these changes, you need to Regenerate Thumbnails to apply them! You can use Regenerate thumbnails plugin to do this.