Thanks for asking.
Please try out following solutions to fix WooCommerce image size issue and let us know how i goes:
- If you have cache plugin activated, please clear cache and test again.
- Test for plugin conflicts. You can deactivate all plugins and see if problem still remains. If it's fixed then you can reactivate plugins one at a time to narrow down.
- Try regenerating your thumbnails. To do that you need to install Regenerate Thumbnails plugin. After installing the plugin, navigate to Tools > Regen Thumbnails > Click Regenerate Thumbnails. You can also refer following tutorial from our knowledgebase.