Fixed a bug that prevented audio files working correctly in the question text. Thanks to Matthias Giger for reporting this. Fixed an issue that prevented any files being inserted into the introduction area. Improved phpdoc of the source code.
Thanks for advice and support to Tim Hunt,Nadav Kavalerchik,Matthias Giger,German Valero and others in the Moodle forums.
It is not possible to insert images into the welcome text area using the editor menu, but you can paste images into that area.