Description:
One of the variants has an invalid image_for_option. The image_for_option must be one of these: {'hull', 'sails'}. The first variant sets the options for the entire listing and you can only have 2 option_names.
This means your image_for_option entry does not match one of the option#_name values provided. In this example, we used sails for option1_name and hull for option2_name.
Solution:
Change your image_for_option entry to match one of the option#_name values you have entered.
For more information about image_for_optipn visit the Documentation page.