Is the Woocommerce Additional Variation Images not working for you? Here are some troubleshooting tips to help you move forward.
Switch to a default theme.
To check for a theme compatibility issue, temporarily enable the Twenty Twelve or Twenty Fifteen theme. Test to see if Woocommerce Additional Variation Images is now working. If so, your original theme was incompatible with the plugin.
Disable other plugins, one at a time.
If your theme doesn’t appear to be the issue, test for plugin compatibility. Disable all plugins except Woocommerce Additional Variation Images and WooCommerce. Test, then add enable one additional plugin and test every time to see which one is causing the conflict.