Fix panic in imaginator when uploading image with no previous image.
Fix panic in imaginator when uploading image with no previous image.

This bug was introduced with the optimisations on 12-May-2018 in
commit 34f93e90e2e49984ea826fb997b00ba1bea2313e.

rgooch/Dominator,Symantec/Dominator,Symantec/Dominator,Symantec/Dominator,rgooch/Dominator,rgooch/Dominator