DrupalBin

function phptemplate_views_filters($form) {
  if ($form['#view_name'] == 'space') {
      //$form['filter2']['#type']='radios';
      $form['filter2']['#size']=15;
      $form['submit']['#theme'] = 'button';
          $form['submit']['#button_type'] = 'image';
          $form['submit']['#attributes'] = array(
            'src' => 'http://localhost:8888/custard/sites/all/themes/zen/custardfactory/images/search.jpg',
            'alt' => t('Search'),
          );
  }
  return theme_views_filters ($form);
}

function phptemplate_button($element) {
  // following lines are copied directly from form.inc core file:
  // Make sure not to overwrite classes
  if (isset($element['#attributes']['class'])) {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
  }
  else {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'];
  }
  // My change is type="' . (($element['#button_type'] == "image") ? 'image' : 'submit' ) . '"
  return '<input type="' . (($element['#button_type'] == "image") ? 'image' : 'submit' ) . '" '. (empty($element['#name']) ? '' : 'name="'. $element['#name'] .'" ')  .'id="'. $element['#id'].'" value="'. check_plain($element['#value']) .'" '. drupal_attributes($element['#attributes']) ." />\n";
}