How can Docker images be shared?

Docker images can be shared effectively by pushing them to a Docker registry, such as Docker Hub. This method allows users to store and distribute their images in a centralized and accessible location, enabling easier collaboration and deployment in different environments. When an image is pushed to a registry, it can be easily retrieved and pulled by other users or systems, fostering a streamlined process for sharing applications packaged as images.

Using a Docker registry provides several advantages, including version control, security features, and easy access for multiple users or teams from various locations. Registries can also host both public images that anyone can access and private images that require authentication.

While images can be saved locally or copied manually, these methods do not facilitate easy sharing or collaboration between teams or across different systems. The use of a 'docker share' command does not exist in Docker's command-line interface, making it an incorrect option. Hence, pushing images to a registry like Docker Hub is the optimal and most common way to share Docker images securely and efficiently.