Support for category images in core

CREATE TABLE associated_image (
  iid int(10) unsigned NOT NULL,
  type varchar(255) NULL,
  class varchar(255) NULL,
  path varchar(255) NULL,
  PRIMARY KEY (iid)
);

/**
 * Call this function from your theme or other php code to display the
 * image associated with the given object id.  An html <img> tag will be returned
 * if an image is found.  The format of the link can be modified with the
 * tags parameter.
 *
 * @param  int     $id	 id of term, node, or other object.
 * @param  string  $type type of object image associated with, e.g., 'term', 'node'
 * @param  string  $class class of image, e.g., 'thumb' (for thumbnail version), 'full'
 * @param  string  $tags optional tags to add into the <img src=''> link
 * 
 * @return string  An html <img src> link.
 */
function associated_image_display($id, $type = 'term', $class = 'full', $tags = NULL) {
  global $user;

  if (user_access('access associated images') &&
      !$user->associated_image_disable_images) {
    // do lookup, return full display path
    if ($image = db_fetch_object(db_query('SELECT path FROM {associated_image} WHERE type = %s AND class = %s AND iid = %d', $type, $class, $id))) {
      $image->url = file_create_url($image->path);
    }
    else if (variable_get('associated_image_recursive', 0)) {
      // walk up the taxonomy hierarchy and look for an image
      if($type == 'node') {
        $tids = taxonomy_node_get_terms($node->nid);
        $tid = $tids[0]->tid;
      }
      if ($image = db_fetch_object(db_query('SELECT path FROM {associated_image} WHERE type = %s AND class = %s AND iid = %d', 'term', $class, $tid))) {
        $image->url = file_create_url($image->path);
      }
      else {
        while ($parent = db_fetch_object(db_query('SELECT t.tid FROM {term_hierarchy} h, {term_data} t WHERE h.parent = t.tid AND h.tid = %d ORDER BY weight, name', $tid))) {
          $tid = $parent->tid;
          if ($image = db_fetch_object(db_query('SELECT path FROM {associated_image} WHERE type = %s AND class = %s AND iid = %d', 'term', $class, $tid))) {
            // we found a parent with a configured image, use it
            $image->url = file_create_url($image->path);
            break;
          }
        }
      }
    }
    if ($image->url) {
      list($image->width, $image->height) = getimagesize($image->path);
      // handle image resizing
      switch (variable_get('associated_image_resize_' . $class, 0)) {
        case 3: // exact
          if ($width = variable_get('associated_image_width_' . $class, 0))
            $image->width = $width;
          if ($height = variable_get('associated_image_height_' . $class, 0))
            $image->height = $height;
          break;
        case 2: // not less than
          if (($width = variable_get('associated_image_width_' . $class, 0)) &&
              ($width > $image->width)) {
            $width_scale = $image->width / $width;
          }
          if (($height = variable_get('associated_image_height_' . $class, 0)) &&
              ($height > $image->height)) {
            $height_scale = $image->height / $height;
          }
          if ($height_scale || $width_scale) {
            if ($width_scale && $height_scale)
              $scale = min($width_scale, $height_scale);
            else
              $scale = $width_scale ? $width_scale : $height_scale;
            $image->height = $image->height / $scale;
            $image->width = $image->width / $scale;
          }
          break;
        case 1: // not greater than
          if (($width = variable_get('associated_image_width_' . $class, 0)) &&
              ($width < $image->width)) {
            $width_scale = $image->width / $width;
          }
          if (($height = variable_get('associated_image_height_' . $class, 0)) &&
              ($height < $image->height)) {
            $height_scale = $image->height / $height;
          }
          if ($height_scale || $width_scale) {
            $scale = max($width_scale, $height_scale);
            $image->height = $image->height / $scale;
            $image->width = $image->width / $scale;
          }
          break;
      }
      return "<img src='$image->url' width='$image->width' height='$image->height' $tags />";
    }
  }
  return '';
}