When you set an image in a question from the combo 'Image to display' (not in the html) the image is not displayed in the quiz.

If you set the debuging messages you'll get this notice:
    Notice: Undefined variable: courseid in /www/moodle/lib/questionlib.php on line 1508

There's an error in the function get_question_image($question) from the moodle/lib/questionlib.php

The solution:
around line 1508
    $img = get_file_url("$courseid/{$question->image}");
should be
    $img = get_file_url("$coursefilesdir/{$question->image}");

So just need to change $courseid to $coursefilesdir

We test the solution on a 1.9.2 moodle with a 8.2.4 postgres installed in a SUSE Linux Enterprise Server 10 SP1