Adds a custom watermark font.

function hook_iek_watermark_font() {
  $path = url(drupal_get_path('module', 'iek') . '/fonts');
  return array(
    'a_cut_above_the_rest' => array(
      'name' => 'a_cut_above_the_rest',
      'title' => t('A Cut Above The Rest'),
      'path' => $path,
    ),
  );
}

Alters an existing watermark font.

function hook_iek_watermark_font_alter(&$fonts) {
  if (isset($fonts['a_cut_above_the_rest'])) {
    $fonts['a_cut_above_the_rest']['title'] = t('Custom title');
  }
}

Adds a custom overlay image. It should be a PNG file.

function hook_iek_overlay() {
  $path = url(drupal_get_path('module', 'iek') . '/overlays');

  return array(
    'basic' => array(
      'name' => 'basic',
      'title' => t('Basic'),
      'children' => array(
        'basic_001_1024x768' => array(
          'name' => 'basic_001_1024x768',
          'title' => t('Basic 001 - 1024x768'),
          'path' => $path . '/basic',
          'file' => 'basic-001-1024x768.png',
        ),
        'basic_001_768x1024' => array(
          'name' => 'basic_001_768x1024',
          'title' => t('Basic 001 - 768x1024'),
          'path' => $path . '/basic',
          'file' => 'basic-001-768x1024.png',
        ),
        'basic_001_600x600' => array(
          'name' => 'basic_001_600x600',
          'title' => t('Basic 001 - 600x600'),
          'path' => $path . '/basic',
          'file' => 'basic-001-600x600.png',
        ),
      ),
    ),
  );
}

Alters an existing overlay image.

function hook_iek_overlay_alter(&$overlays) {
  $overlays['basic']['title'] = t('Custom title');
}