Migrate taxonomy images from Drupal 5

The following class was used to migrate taxonomy term images from Drupal 5's Taxonomy Image module into a proper Drupal 7 entity field. You'll want to adjust class and field names appropriately for your use case.

Note: Taxonomy Image in Drupal 5 did not make use of the files table, so you need to specify a path to your taxonomy images in the prepareRow() method.

class GWJTermImageMigration extends DrupalTerm5Migration {

  public function __construct(array $arguments) {
    $this->sourceFields['field_image'] = t('Constructed source image field');
    $this->sourceFields['field_image:title'] = t('Constructed source image title field');
    $this->sourceFields['field_image:alt'] = t('Constructed source image alt field');
    $this->sourceFields['field_image:source_dir'] = t('Constructed source image source directory field');
    $this->sourceFields['field_image:destination_dir'] = t('Constructed source image destination directory field');
    $this->sourceFields['field_image:destination_file'] = t('Constructed source image destination file field');
    parent::__construct($arguments);

    $this->addFieldMapping('field_image', 'field_image');
    $this->addFieldMapping('field_image:file_class')->defaultValue('MigrateFileUri');
    $this->addFieldMapping('field_image:title', 'field_image:title')->defaultValue('');
    $this->addFieldMapping('field_image:alt', 'field_image:alt')->defaultValue('');
    $this->addFieldMapping('field_image:language')->defaultValue(LANGUAGE_NONE);
    $this->addFieldMapping('field_image:source_dir', 'field_image:source_dir')->defaultValue('');
    $this->addFieldMapping('field_image:destination_dir', 'field_image:destination_dir')->defaultValue('');
    $this->addFieldMapping('field_image:destination_file', 'field_image:destination_file')->defaultValue('');
    $this->addFieldMapping('field_image:file_replace')->defaultValue(FILE_EXISTS_REPLACE);
    $this->addFieldMapping('field_image:preserve_files')->defaultValue(FALSE);
  }

  protected function query() {
    $query = parent::query();
    $query->leftJoin('term_image', 'ti', 'td.tid = ti.tid');
    $query->addField('ti', 'path', 'term_image_path');
    return $query;
  }

  public function prepareRow($row) {
    if (parent::prepareRow($row) === FALSE) {
       return FALSE;
    }
    $file_base_path = variable_get('gwj_migrate_file_path');
    if (!empty($row->term_image_path)) {
      $path = $file_base_path .'/'. preg_replace('/^files\//', '', $row->term_image_path);
      $pathinfo = pathinfo($path);
      $row->{'field_image'} = $pathinfo['basename'];
      $row->{'field_image:source_dir'} = $pathinfo['dirname'];
      $row->{'field_image:destination_dir'} = 'public://term_images';
      $row->{'field_image:destination_file'} = $pathinfo['basename'];
      $row->{'field_image:title'} = $row->name;
      $row->{'field_image:alt'} = $row->name;
    }
  }
}