It looks like custom images are ignored on save
and then in the log i see this:

Provisioned slave jenkins-1e0de21e-2e55-438f-9d50-f413a9918538 failed to launch
java.lang.AssertionError
at com.dubture.jenkins.digitalocean.SlaveTemplate.provision(SlaveTemplate.java:170)
at com.dubture.jenkins.digitalocean.Cloud$1.call(Cloud.java:287)
at com.dubture.jenkins.digitalocean.Cloud$1.call(Cloud.java:282)
at jenkins.util.ContextResettingExecutorService$2.call(ContextResettingExecutorService.java:46)
at java.util.concurrent.FutureTask.run(FutureTask.java:262)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)

Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud provision
Provisioning digitalocean droplet for label !master&&!pytest, excessWorkload 1
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud addProvisionedSlave
Adding provisioned slave null
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud countCurrentDropletsSlaves
countCurrentDropletsSlaves(null)
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud getDroplets
Listing all droplets
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud countCurrentDropletsSlaves
countCurrentDropletsSlaves(null)
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud getDroplets
Listing all droplets
Jul 13, 2015 10:44:59 PM INFO com.dubture.jenkins.digitalocean.Cloud addProvisionedSlave
Provisioning for AMI null; Estimated number of total slaves: 0; Estimated number of slaves for imageId null: 0