In outline block the image for certificate doesn't appear

The image misc/watchdog-ok.png is not displayed. Solution:

Add in includes/course.outline.inc, after line 438 the line

$step['image'] = 'misc/watchdog-ok.png';

So between the existing coding:
if ($courseObject->access('take')) {
// User can take this course object.
$step['link'] = $courseObject->getUrl();

if (!$prev_req || $prev_req->getFulfillment()->isComplete()) {
$step['status'] = 'Begin';
//PATCH: addition for showing image when certificate is complete:
$step['image'] = 'misc/watchdog-ok.png';
}