Usually, https://serverfault.com/a/268727/126950:

  • snapshot = an exact capture of what a volume looked like at a particular moment in time, including all it's data.
  • image = a total snapshot of a system (doesn't save the user data)

However, http://docs.openstack.org/folsom/openstack-ops/content/snapsnots.html says

In OpenStack, an instance snapshot is an image. The only difference between an image that you upload directly to glance and an image you create by snapshot is that an image created by snapshot has additional properties in the glance database.

So why does OpenStack distinguish images from snapshots?

  • actually i think for organization purposes on dashboard, it's a good idea to distinguish snapshot from image at least on GUI, otherwise in a live environment you got a long list of images some of which are snapshots.. – Erik Jan 30 '17 at 19:07

There's no meaningful difference between the two, and it's only the OpenStack dashboard that makes a distinction between between images and snaphots. I submitted this issue as a UI bug a while back, and it has been fixed in the upcoming (havana) release of OpenStack.

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  • 2
    Thanks for this answer. Short of upgrading Openstack, is there any way to make a snapshot show up as an image in the UI? Or otherwise "convert" a snapshot to an image? – JDS Dec 15 '14 at 22:50

I don't have enough rep to comment on JDS's Question directly, but here is the answer: You have to download the snapshot and create an image out of it via glance, so something like this:

source openrc
glance list-images #find your snapshots ID
glance image-download "snapshot-ID" --file "some name".qcow2 #without the ""
glance image-create --name "desired image name" --disk-format qcow2 --container-format bare --min-disk="size of the virtual disk of the snapshot" --is-public True --is-protected True --file "some-name".qcow2 #again without the ""
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