Massively setting default images?

[bandini]

Hi guys. I have imported over 2300 products to my Prestashop catalogue via CSV. What I'd like to do now is as follows:

 

So I have several images for most products, and different color combinations for most of them, and I would like that all the products that are available in red have the image of the product in red as default, so the red thumbnail appears in the web. I have managed to set all red combinations as default, but I don't know how to set the red image as default for all products that have it. Is there a way around this? Thank you very much!