Datafeedr and other imports from affiliate feeds frequently have multiple choices of image URLs.
A feature request has been made to modify this plugin to allow admin to choose multiple image URLs in the product meta data and for the plugin to automatically detect which URL for this product has the larger, better quality image.
It will be presumed that ‘larger’ equals better quality.
This image size comparison will occur IF this option is enabled, and IF this product has both (or multiple?) fields populated.
The image size comparison will occur only the first time the product is loaded, and from then on the external image URL will be ‘set’. To override it manually, you will then have to manually edit the external image URL field in the product editing page.