function image_style_delete in Drupal 7
Deletes an image style.
Parameters
$style: An image style array.
$replacement_style_name: (optional) When deleting a style, specify a replacement style name so that existing settings (if any) may be converted to a new style.
Return value
TRUE on success.
1 call to image_style_delete()
- image_style_delete_form_submit in modules/image/ image.admin.inc 
- Submit handler to delete an image style.
File
- modules/image/ image.module, line 725 
- Exposes global functionality for creating image styles.
Code
function image_style_delete($style, $replacement_style_name = '') {
  image_style_flush($style);
  db_delete('image_effects')
    ->condition('isid', $style['isid'])
    ->execute();
  db_delete('image_styles')
    ->condition('isid', $style['isid'])
    ->execute();
  // Let other modules update as necessary on save.
  $style['old_name'] = $style['name'];
  $style['name'] = $replacement_style_name;
  module_invoke_all('image_style_delete', $style);
  return TRUE;
}