Including my answer to sati here as well for future reference:
"Missing playable component" means that the version does not contain a component with the required metadata to mark it as a reviewable component.
For local installations, we try to encode videos to a web playable format, but do not support encoding images at this point. To make the images viewable you can do one of the following:
Publish versions that fulfills the requirement via the API: Publishing for web review
Run an event listener which automatically updates images to be reviewable: Image 'encoder' for local installations.