We are using all imported to import products into the system.
We are importing multiple products per variant, as such these are saved in the postmeta table with meta_key “_product_image_gallery”. However it would seem that on your guys side you are not using this field for variant products but rather wd_additional_variation_images_data. In the admin we also do not see these variant images.
Is this the reason why you guys are using your own field as opposed to the “_product_image_gallery”?
A variable product is a bit customized: a gallery per variant is added, and most likely, you are right, import files do not coincide, that is why you will have to upload images manually.
If you have any questions please feel free to contact us.