Here you will find all necessary information about images.
Product image - this is the main product image and will be used by Shopify in catalog and related products.
Recommended image sizes: minimum 1000 x 1000px, maximum 4000x4000px
Scene - this will be used as a base layer or background for your build; you can pick a color or use an image.
Recommended image size: minimum 1600x900 or 16:9 aspect ratio; recommended format: PNG.
Thumbnail image - this is an option icon; you can pick a color or use an image.
Recommended image size: 400x400 or 1:1 aspect ratio; recommended format: PNG.
Layer image - layer image will be placed over your scene.
Layer image should be exactly the same size as your scene and the same size as your other layers.