Drupal 6 - Create imagecache preset via code

The following create an imagecache preset for Drupal 6.

PHP CODE :
// Preset
$imagecachepreset = new stdClass ();
$imagecachepreset->presetname = 'MYPRESETNAME';
drupal_write_record('imagecache_preset', $imagecachepreset);

// Action
$imagecacheaction = new stdClass ();
$imagecacheaction->presetid = $imagecachepreset->presetid;
$imagecacheaction->module = 'imagecache';
$imagecacheaction->action = 'imagecache_scale_and_crop';
$imagecacheaction->data = array(
'width' => '200',
'height' => '200'
);
drupal_write_record('imagecache_action', $imagecacheaction);

source : http://drupal.org/node/163561