If you have more than 10 Variation SKUs in your Etsy listing, some of the images may not appear on your Etsy variation listing. This is due to the maximum number of images allowed in Etsy which is set to 10

Selro will send the first 10 variation images and the remaining variation SKUs will have the first image in the list.

https://www.etsy.com/seller-handbook/article/showcase-your-products-with-more-images/158634470078#:~:text=More%20photos%3A%20Now%2C%20when%20you,about%20the%20variations%20you%20offer.