Thanks for writing in! I have logged in and I found out that you are using Jetpack plugin's Photon module. Please keep in mind that Photon module caches your images even if you already have regenerated your thumbnails. Please disable Photon module and see the difference in the images. It is also best if you review the pros and cons of using Photon module. You can check it here: https://jetpack.com/support/photon/
It is also better to note the changes in the product images with the recent changes in WooCommerce. Please check out this thread:
Hope this helps.