In order to import and link multiple gallery images to the product, the following fields should be added to the import profile:
Sku or entity_id fields are added for the extension to identify the product and assign the rest of the mapped data to it. It is possible to define the identification attribute in the 'Import Settings' tab of the profile.
Value_id is the value that is used for the identification of the particular gallery image. It can be either looked up in the "catalog_product_entity_media_gallery" and "catalog_product_entity_media_gallery_value" tables, or you can put a number that exceeds the quantity of existing images, for instance "910000", and the module will automatically generate the correct ID according to the data from the tables.
Attribute_id is the ID of the 'media_gallery' attribute. By default, the extension adds the 'EAV Attribute Code to Id' modifier to transform the attribute code to the ID. This means, that 'media_gallery' value can be inserted in the import file, and there is no need to check the attribute ID additionally.
The value field should contain either the path to the image in case it's already imported to Magento, or the URL of the image, for the extension to download it to Magento and link to the product. In case several images are to be linked to a product, each value should be defined from a new line.
Kindly note that the directory, where the images are located, or should be downloaded, must be defined in the 'Import Source' tab of the profile.
Media_type for the images import is 'image'.
Entity_id is the ID of the product where the images should be linked. It can be located on the Product grid in the 'ID' column.
Please follow this link to check the sample file for import.