A product Pin should let someone understand the item before opening the destination page. Show the complete part that matters: the handle on a bag, the base of a lamp, the shape of a bottle, or the finish on a table. A fashionable crop that removes those details can make the picture attractive but less useful to a potential buyer.
Pinterest's creator guidance describes a 2:3 image such as 1000×1500. This page selects that shape for a standard product image. It is not a product catalogue validator or a promise that every shopping placement has the same requirements. Confirm the requirements of the publishing route you actually use.
Start with an original product photograph or an export from your design file. Avoid a screenshot from the shop page if you can access the image itself. Screenshots can include interface elements and scaled text, while the original gives you more control over the crop and the detail that survives reduction.