result grid > display 2ndary image on every 2nd grid

[william-johnson-bloomreach]

This is a specific request, from a luxury customer. But the idea is interesting.
Goal is to have an elegant, consistent layout of images, alternating between main and secondary image of products.

Request:
On a product result grid, alternate product images:

• have slots with odd numbers (1, 3, 5, 7, 9, etc....) display the main image of product
• slots with even numbers (0, 2, 4, 6, 8, etc...) display the secondary image of the product
  Do maintain the image switch on hover