Change displayed variant image according to collection

Hi ..new to this ! i created a store filled it with products and their color variants so now i have something like this product "t-shirt" with five different color variants( Blue green,etc) the original color (white ) is which is displayed in the store . now i want to add this product to a new collection called blue .. but i want it to appear there with the connected image to the color blue ! Any hints or ideas greatly appreciated

Thanks .