Drupal 6 - make external image_buttons work like D7

mymodule.php

<?php
//you could also add this to your theme's template.php file, by replacing "phptemplate_image_button" with "themename_image_button" in the function name.
function phptemplate_image_button($element) {
  // Make sure not to overwrite classes.
  if (isset($element['#attributes']['class'])) {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'] .' '. $element['#attributes']['class'];
  }
  else {
    $element['#attributes']['class'] = 'form-'. $element['#button_type'];
  }
  
  $src_uri = $element['#src'];
  
  $data = explode('://', $src_uri, 2);
  $scheme = count($data) == 2 ? $data[0] : FALSE;
  
  if (!$scheme) {
    $src_uri = base_path() . '/' . $element['#src'];
  }

  return '<input type="image" name="'. $element['#name'] .'" '.
    (!empty($element['#value']) ? ('value="'. check_plain($element['#value']) .'" ') : '') .
    'id="'. $element['#id'] .'" '.
    drupal_attributes($element['#attributes']) .
    ' src="' . $src_uri . '" ' .
    (!empty($element['#title']) ? 'alt="'. check_plain($element['#title']) .'" title="'. check_plain($element['#title']) .'" ' : '' ) .
    "/>\n";
}

In my case it's a "Pay with PayPal" button. Image buttons make sense, they are valid HTML, no?

IIRC inputs typed to image send the coordinates on the image where they clicked, so technically they're sending more data (although not much).
button elements can be assigned as submit buttons natively whereas image types would need JS in order to dispatch submit form on click/enter.

Both are valid. (S/T/F)
Button elements are more useful in most cases.

Thanks e1nherjar. I tried disabling javascript in Firefox and click+enter still worked on the image button.

You're right about the coordinates of the click event, in my case it's no biggie.