$result = $query->entityCondition('entity_type', 'node')
    ->entityCondition('bundle', 'reference')
    ->propertyCondition('promote', 1)
    ->propertyOrderBy('created', 'DESC')
    ->pager(12)
    ->execute();

$query = db_select('node', 'n');
$query->join('field_images', 'fi', 'n.nid = fi.nid');
...rest of query

$result = $query->entityCondition('entity_type', 'node')
    ->entityCondition('bundle', 'reference')
    ->propertyCondition('promote', 1)
    ->propertyCondition('field_images', 1)
    ->propertyOrderBy('created', 'DESC')
    ->pager(12)
    ->execute();