Migration from Drupal 7 Core Image Field to Media Module File Field

I am working on a D7 -> D7 migration (they want a clean start as they are re-defining many entity/field structures which is why they are migrating D7->D7).

The legacy D7 site uses D7 core Image fields. The new site users Media Module/File fields and File Entities. Any idea of the best way to migrate these fields?

Currently my code looks like:

<?php

// This example is migrating a D7 taxonomy to a D7 content type
// There is one D7 Image field in the source taxonomy that needs migrated to a D7 File field in the destination node)

class TaxonomyExampleMigration extends DrupalTerm7Migration {
  public function __construct($arguments) {

    $arguments = array(
        'description' => t('Migration of legacy Example taxonomy terms to nodes.'),
        'source_connection' => 'xxxx',
        'source_version' => 7,
        'source_vocabulary' => 'example',
        'destination_vocabulary' => 'example',
    );
    parent::__construct($arguments);

    $this->machine_name = 'TaxonomyExample';

    $this->destination = new MigrateDestinationNode('example');

    // Key Mappings
    $this->map = new MigrateSQLMap($this->machineName,
      array(
        'tid' => array('type' => 'int',
                       'unsigned' => TRUE,
                       'not null' => TRUE,
                      )
      ),
      MigrateDestinationNode::getKeySchema()
    );

   // this does not work
   $this->addFieldMapping('destination File field here','source D7 core image field here');

...


?>

Thanks for your help!
captaindav