EDIT

  $taxon_media_filter_choice = variable_get(CDM_TAXON_MEDIA_FILTER, unserialize(CDM_TAXON_MEDIA_FILTER_DEFAULT));

  $mediaQueryParameters['includeTaxonDescriptions'] = (boolean) $taxon_media_filter_choice['includeTaxonDescriptions'] != 0;

  $mediaQueryParameters['includeOccurrences'] = (boolean) $taxon_media_filter_choice['includeOccurrences'] != 0;

  $mediaQueryParameters['includeTaxonNameDescriptions'] = (boolean) $taxon_media_filter_choice['includeTaxonNameDescriptions'] != 0;

  $mediaQueryParameters['includeTaxonomicChildren'] = variable_get('cdm_images_include_children', 0) != 0;

  return $mediaQueryParameters;

    array(

        'includeTaxonDescriptions' => 'includeTaxonDescriptions',

        'includeOccurrences' => 0,

     )

  ));

          'includeTaxonDescriptions' => 'Media in taxon descriptions',

          'includeTaxonNameDescriptions' => 'Media in name descriptions',

          'includeOccurrences' => 'Media related to specimens and occurrences',

      ),

      '#description' => 'This filter configures which images should be taken into account.',

  );