Which solution will meet these requirements?

Explanations:

Amazon S3 with S3 Cross-Region Replication (CRR) allows for automatic scaling, versioning of objects, and maintaining multiple copies of data across different AWS Regions. This meets all requirements: automatic scaling as new images are added, support for versioning, and redundancy across regions.

Amazon Elastic Block Store (EBS) does support snapshots and can be shared in another region, but it does not inherently provide versioning for individual files like S3 does. Additionally, EBS is primarily designed for use with EC2 instances, not for a scalable object storage solution.

Amazon Elastic File System (EFS) provides scalable file storage with regional availability but does not support automatic cross-region replication or versioning of files as S3 does. EFS is also designed for use with EC2 instances, making it less suitable for a repository that needs automatic scaling and version control.

AWS Storage Gateway Volume Gateway is designed for hybrid cloud storage and provides a way to connect on-premises applications to AWS storage. However, it does not natively support automatic scaling, versioning of individual images, or maintaining multiple copies across regions as required for this solution.