For an e-commerce product detail page, is it better to have the item picture thumbnails laid out vertically to the left side of the main picture, or laid out horizontally to the bottom of the main picture? Both type of designs are prevalently used.
I'm looking at two reasons why vertical placement works best for product thumbnails:
Majority of web users are already familiar with this approach as the top e-commerce portals such as Amazon, Walmart, Zappos, Flipkart etc... they all use vertical thumbnails. By placing it horizontally; I might ask users to learn a new way to interact, and eventually break their metal model.
Vertical placement helps in viewing all three elements (Thumbnail, Product Picture, and the zoomed picture) in one line without a lot of eye movement - which follows users natural reading pattern like the f-shaped-pattern.
I didn't find any UX guidelines on this topic, but I will keep looking.
it depends, depends on the product, the direction of rotation the product images are in, and the layout of your product screen.
in fashion e commerce i've notice vertical is more common. that also might be due to very similar layouts fashion e commerce uses.
a good example how Warby parker does is for their glasses https://www.warbyparker.com/eyeglasses/men/durand/crystal-blue-jay (scroll down and hover over the face) even tho there are no thumbnails. you could assume if there were, they would be horizontal as to match the angle of the image with the hand movement.