Question

<?php 
//...

$tags = $api->photos_search(array(
    'text' => 'stuff',
));

foreach ($tags['photo'] as $photo) {
    // want to get get the user's actual username from the the "owner"
    $ownerId = $photo['owner'];
    // getUsernameById($ownerId); // <-- how do you do this?
}

Answer 1

I have never used that library, but according to the Flickr API, the function is called originally flickr.people.getInfo.

That PHP class follows this naming convention. I would try

$userinfo = $api->people_getInfo($ownerId);
var_dump($userinfo['username']);

Good luck!