Add _warnings_

Use case https://github.com/startupdotdev/forever721/pull/7/files#diff-a2a171449d862fe29692ce031981047d7ab755ae7f84c707aef80701b3ea0c80R40 here if we don't find an image, then we are not really grading well.

This will mean that we don't count towards the grade too.