The concept of image in Docklet is similar to that in Docker, i.e., a readonly template to create containers. But there are some differences.
Since Docker mainly focuses on LXC container in IaaS level, its images are very free and versatile. Users can customize and make their own images and then upload them to the docker hub. Usually one Docker image has only the environment of one specific application. For example, a Docker image may have a full Ubuntu operating environment, in which there is only the Apache web server software.
Docklet is a bit different. Docklet focuses on Workspace and vcluster, therefore has special restrictions about images, not supporting uploading user-made images. The Docklet administrator will make one or more public base image according to the common requirements of the enterprise, containing the needed software packages to support Workspace, together will some programming tools and frameworks such as MPI, Spark, Python and R. Since the Docklet public base images are shared by all users, therefore is usually larger than typical Docker containers.
If users can not find needed software tools in the public base image, they can install them in their Workspace. They can then save their Workspace as private image, and can choose to share it with others.