Hi
1. Please looking at the following questions.
Can I know your site link that I can check it on my mobile?
Have you changed or added CSS file?
Also, how about the demo site on your mobile?
2. Check the documentation, in “Initialization” section, I mentioned that change the default media size to double size
"Please note, if you actived WooCommerce plugin, you should also change the default image size in "Woocommerce > setting > catalog > image options", just change all default size to double size, for example, change 150px to 300px."
Refer to this screenshot https://www.dropbox.com/s/7cfmvfyidsoqj6u/woocommerce_image_size.png
Thanks