When you have multiple product variants, sometimes it’s more convenient to show a customer everything you have to offer at a glance.
Let’s say you sell chairs. The two chairs are identical in every aspect except one has a headrest and the other doesn’t. Thus, these chairs are variants of each other. How do you convey this information to the customer in as little time as possible? An image showing both chairs obviously.
But the chair headrest example is an easy one. What if we add colors to the mix? If each chair comes in five colors then there are now ten distinct variants of the chair. But you can’t have a photograph showing all the ten available variations. The visual clutter will do far more harm than good.
So while it’s a good idea to have a single photograph showing all your product variations, once you get beyond three variations, things get testy. With mobile phone screens being what they are, photographs can only be so large.
This is also made worse by the fact that photographs don’t take up the whole screen. When a user is scrolling through a product list, the photograph for each item will at best take up a tenth of available screen real estate. A tenth of an already small phone screen isn’t much.
For your product images to stand out, they need to be as uncluttered as possible. Fitting ten items into a single photograph may look fine but when that image is condensed to only occupy a tenth of the screen, it just becomes a blur.
Even if the user clicks on the product images and they expand to take up half the screen, ten items are still a lot for humans to focus on. So, as a general rule, only put your variants in a single image if you have three or fewer. You can push it slightly but you should never go beyond five.
The variants you should focus on should be as visually distinct as possible, think colors or patterns. If you have more than three variations, show the existence of additional variations with either swatches or thumbnails.
NB: Putting the three variants of your product into one photograph does not excuse you from showing individual photos of each variant.