Problem With Woocommerce Images

I have looked, but can’t seem to find the solution to my issue. I’m having an issue with woocommerce images, more specifically the “gallery” images under the main image on a single product page. Here is an example:
http://alkalitest.com/product/d1s-morimoto-xb-hid-d/
The image is blurry, I’ve seen documentation on how to change the main image, but the thumbnail section under the customizer doesn’t seem to have an option to adjust the resolution of that one. Any help is greatly appreciated. Thanks!

Hello there,

Try to regenerate the thumbnail images with the new specified size using this plugin:

Regards,
Kharis

That didn’t seem to fix the issue. Do you have any other suggestions? Thanks!

I fixed the issue before using the product thumbnails option, but that option doesn’t seem to be in the customize tab anymore.