Type of the catalog preview. Use 'product' to set a first product image as preview, 'business_profile' to set the business profile pic as preview, 'thumbnail' to set a custom small jpeg image from 'preview' param as preview, 'media' to set a custom large image from 'media' param as large preview, 'style1' to set a isometric style for catalog preview stub, 'style2' to set a flat style for catalog preview stub, 'style3' to set a WA style for catalog preview stub, or 'none' to not set a preview. If not set, the default is product.