One of the advantages of shopping in a physical store is that you can always know the size of every item with a single look. You never have to worry about whether that couch will fit in your living room or that carpet will fit on your floor or whether that refrigerator would pass through your door. You never have to worry about whether that blender you’re buying is too large or too small for your needs. You just look at the product and you know.

Online shoppers never have such assurances. While photographs show you exactly how a product looks like, they’re terrible at actually showing you the size of the product due to the usage of vastly differing scales. A photograph of a cup and a photograph of a refrigerator may have the same image dimensions yet we all know that the standard refrigerator is much larger than a cup.

A lot of sites try to get around this problem by giving product dimensions. While measurements of length, weight, and height help, they still fail due to the way humans perceive size. We determine the size objects in relation to ourselves and other common objects rather than in exact dimensions. 

I don’t think of my refrigerator as six feet tall and three feet wide. I think of it as being about the same height as me and about as wide as my back door.

My blender is about as tall as my plastic waste paper basket but narrower and heavier than the basket. When we see things, we compare them in size to other things we know that have approximately similar dimensions.

This is where an in-scale image comes along. It shows your product photographed in the same context as a product whose size is well known to your customers. Take the wall hanging below for example:

 Shown alone, determining its size just by looking at it is a tall order.

But showing it hanging behind a two-seater couch, however, makes it very easy for your customers to guess its approximate size without having to look at the dimensions and doing a lot of math.