Drupal Search field tweaks

This CodeLet tweaks the way the search field is displayed in search block. It adds an image button instead of normal submit button.

CodeLet: 

<?php

/**
* @file
*
* Tweaks the search feature and search fields
*
* @author DrupalD
*
*/

/**
* Implementation of hook_form_FORM_ID_alter
*
* @param $form
* @param $form_state
* @author DrupalD
*/
function search_tweak_form_search_theme_form_alter(&$form, $form_state) {
$form['submit'][''] = 'image_button';
$form['submit'][''] = drupal_get_path('module', 'search_tweak') .'/search.png';
}
?>

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Image: 
Drupal Search field tweaks | Druapl Developer