First, check that all images you’ve added to the listing are set to be publicly visible—i.e., that they haven’t been marked under Does not appear in the sales advertisement. For more details on managing images, see this article.
It’s also worth noting that publishing platforms (e.g., Etuovi or Oikotie) may limit the number of images shown in the listing depending on the contract package you have with them. We therefore recommend checking your service agreement with the platform.