If a file is created that doesn't have a type that is picked up by a preview processor, does it forever sit in `PENDING` ? If so, do you think it would be better if the preview processor had full control over setting this value, such that if the file isn't something that gets processed, it never has a previewStatus assigned to it? The PP would do something like:

a) Set pending when it starts (not even sure this would be 100% necessary?)
b) When complete, set to `error` or `done`