Take as example this question: http://drupal.stackexchange.com/questions/3715/insert-images-with-media.  
The OP updates the question one hour later the question was asked, to report they found the solution.

What should be done with such questions, in the case the OPs don't add the solution as answer after a week, and they have being asked to write what they found be the solution as answer? Should the questions be closed as too localized?