In the OpenStack context, an image is a file that contains a virtual disk from which you can install an operating system on a virtual machine. You create an instance in your OpenStack cloud by using one of the images available.
The VMware Integrated OpenStack image service component natively supports images that are packaged in the ISO, OVA, and VMDK formats. You can also import RAW, QCOW2, VDI, and VHD images, which are automatically converted to the VMDK format during the image creation process.
VMware Integrated OpenStack only support the openstack image save and glance image-download commands for VMDK format image.