How can I get a related Asset of a specific field? I'm trying to grab an Asset which is a child of my Entry...

$criteria = craft()-&gt;elements-&gt;getCriteria(ElementType::Asset);
$criteria-&gt;childOf = $entryId;
$photo = craft()-&gt;assets-&gt;findFile($criteria);


For the most part, this works pretty well. But my entry has multiple Asset fields, and sometimes it grabs the wrong image.

I suspect that I just need to add another parameter to my $criteria, but I can't figure out what... theoretically something to denote which specific field I'm referring to. Any suggestions?
Found it! The specific field can be targeted like this:

$criteria-&gt;childField = 'myFieldHandle';