Why can't I create a Droplet from a snapshot?

You cannot create Droplets in certain datacenters due to limited capacity. If your snapshot is in a limited capacity datacenter, you can’t create a Droplet from that snapshot.

If you have a snapshot in a datacenter where Droplet creation is not availble, transfer the snapshot to another datacenter. You can then create a new Droplet from that snapshot in the new datacenter.

You can see where Droplets are available on the Droplet availability page.

Take a snapshot of your Droplet and then create new Droplet from the snapsnot in the new datacenter.
No, you cannot downsize a Droplet using a snapshot.
Snapshot images are compressed when stored.