Scald: themable atom reference – where to find image path etc.?
Found the answer to my question one of scald's issue pages – and it's not really complicated. Either it's just not well documented, or I just didn't see it:

This gets the SID from the node's array: 

$img = $vars['node']-&gt;field_teaser_image['und'][0]['sid'];


And this fetches the atom reference's object: 

$atom = scald_atom_load($img);


This is how I then load the title of the atom reference image inside template.php:

$vars['img_title'] = $atom-&gt;title;


And the actual filename is inside another object base_entity:

$vars['img_filename'] = $atom-&gt;base_entity-&gt;filename;


Hope this may help somebody some day.