The sf_flickr is for displaying photos from flickr. The form runs a simple free-text search using the flickr API against the value of a field specified by the Administrator and returns a specified number of results.The field will need to be properly setup in field_settings.php. It is better to use an attribute field, or something without verbose text as the whole string will be sent as the search term.
sf_flickr is only available as of 0.7. You will need to have downloaded the phpFlickr API from  and copied it into the directory specified in your $pear_path variable (see env_settings.php). In addition you will need to have acquired an API key from flickr for your specific project.
sf_flickr takes the following extra fields:
'api_key' - REQUIRED - this is the api key gained from flickr 'op_resultnum' - OPTIONAL - this is the number of results to pull (it defaults to 12 if not set).
An example of sf_flickr returning photos of bird species
$conf_mcd_flickr = array( 'view_state' => 'max', 'edit_state' => 'view', 'sf_title' => 'flickr_photos', 'sf_html_id' => 'brd_flickr', // Must be unique 'script' => 'php/subforms/sf_flickr.php', 'sf_nav_type' => 'full', 'api_key' => FILL THIS WITH YOUR OWN API KEY, 'op_label' => 'space', 'op_input' => 'edit', 'op_resultnum' => 12, 'fields' => array( $conf_field_scientific_name ) );