I just looked at our code, and right now, we don't use a default image. I've added it as a task for the the next big SCLogin release to automatically use the default avatar. For now, if you edit the /modules/mod_sclogin/helper.php file, around line 229, you'll see:
if ($avatarURL)
$avatarURL = JRoute::_('images/comprofiler/' . $avatarURL, false);After that, you can set a default image with an else statement, like:
if ($avatarURL)
$avatarURL = JRoute::_('images/comprofiler/' . $avatarURL, false);
else
$avatarURL = 'http://yoursite.com/link-to-default.jpg';I hope that helps,
Alex