The cut, the fabric and the trims of a style stay the same across its colourways; only the colours change. A colourway can be a single shade or a fixed combination, as on a sneaker whose upper, sole and laces each have a colour of their own. In a product catalogue each colourway is normally a variant of one listing, with images of its own.
Shoppers choose a colour from what they see, so each colourway needs an image that shows that colour and no other. Photographing every colourway is one way; producing colour variants from the image of one is another, and the shade should then be compared with the real product, since a screen and a dyed fabric never agree completely.