The sales process is quite similar whether it's in a physical store in a mall or in the digital world, on a website or on Amazon. In order to convince a customer to make a purchase, we need to provide them with all the necessary information about the product and, of course, its benefits and advantages.
Lately, I've come across many sellers who take the size of the product for granted.
The most basic option (which many sellers skip even though it's crucial) is to mention the product's dimensions on one of the images.
However, surveys and research in the US have shown that many customers abandon the sales page and move to a competing product as soon as they can't understand the product's size correctly, especially in low-commitment buying processes (products under $30 more or less).
Now, to the really important part:
Most people in the world (and you can test me with tests on people around you) don't really know how to estimate sizes accurately. They won't be able to show you what 20 or 30 cm is with their fingers, and in most cases, the estimation will be wrong by at least 5-10 cm.
Therefore, to make it easier for your customer and increase conversion rates, I strongly recommend using lifestyle images, especially an image that illustrates the size of the product with well-known world items.
In other words, if you are selling a vacuum cleaner, for example, specify the product's dimensions not in an image with a white background but in an image where the vacuum cleaner is next to well-known items like a stove, a pot, KitchenAid, etc.
The proportions help our brain make a quicker purchase decision.
In the attached image, you can see an example of what happened to me when I ordered a milk frother from the AliExpress app without dedicating too much thought to the dimensions and in the absence of a proportional image of the product in its natural surroundings.