This ability to add images works if you have Image URL's and want to add extra images to products in bulk.
1. Click the "Export Products" icon and an Excel template will be downloaded with all your products in your catalog.
If you have specific SKUs you would like to update, you can use the filter or the search bar to find the SKUs and then click "Export Products"
2. On the export file, there will be a column called (Extra Images) for you to add additional images to each particular SKU.
3. On the template, you may add more than two extra images by inserting a new column and duplicating the title.
Once you've added the image URL's to your products, go to your Brand and upload the file template to your catalog.