I'm doing a site upgrade for a client from Drupal 6 to Drupal 9. This time I decided to dive deeper into the Drupal Migrate API and use it to migrate content. Everything was going smoothly until I ran into image migration. I migrated the files themselves without problems, as well as the content, the only thing I couldn't do was link the file entities to the content entities. On the old (Drupal 6) website they were in the field_news_images, on the new one the field is called field_images.