I thought I'd share this as it frustrates the heck out of me that the default action for images is not "nolink" unless explicitly forced.
In wiki/inc/parser/handler.php - line #772:
//get linking command
if(preg_match('/nolink/i',$param)){
$linking = 'nolink';
}else if(preg_match('/direct/i',$param)){
$linking = 'direct';
}else if(preg_match('/linkonly/i',$param)){
$linking = 'linkonly';
}else if(preg_match('/details/i',$param)){
$linking = 'details';
}else{
$linking = 'nolink';
}
I don't have time to work out how to submit this officially etc. so if someone wants to do so that would be great.
If I had more time I'd tie the default action to a setting in the config page but this serves my purpose.
Hope this helps someone.