External Images prevents Datafeedr from downloading featured images to your site, either when product sets run or when your archive pages load for the first time.
This allows you to build far larger websites without using up all your storage space storing images which are already hosted on affiliate CDNs.
It also integrates with the other Datafeedr widgets to spoof those widgets into using the external images instead of displaying a placeholder.
If you are using Datafeedr, you don’t really need to do anything else – just install the plugin and then run all your product sets. Your site will be far faster since it’s not burning CPU and disk downloading and resizing images all the time.