A container image registry, or OCI (Open Container Initiative) image registry, is a centralized repository that stores container images, which are pre-packaged software units containing everything needed to run an application, including the code, runtime, system tools, and libraries.
One commonly used container image registry is the Docker Registry (docker.io), which is widely adopted in the container ecosystem, but there are also several others available, such as Amazon Elastic Container Registry (ECR), Google Container Registry (GCR), and Azure Container Registry (ACR), accessible through several cloud providers.
This registry gets updated with new versions through the CI pipeline of the application being developed.