I have managed to install openstack on VirtualBox running ubuntu 12.04 desktop as VM using devstack script.I am running Havana. I have created an image using a .vdi file from a Ubuntu Server VM I once created in VirtualBox. Since I came from AWS background I tend to think of OpenStack as a "private AWS" . I have not seen on the web interface any indication of creating an instance from my own images or any existing images. However I have seen lots of command line resource online for lauching/creating instances.
Kindly shed the light
PS: I do not have enough privilege to post an image, I would have shared the interface am looking at