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  if (function_exists($function) && $image->resource = $function($image->source)) {

    if (imageistruecolor($image->resource)) {

      return TRUE;

    }

    else {

      // Convert indexed images to truecolor, copying the image to a new

      // truecolor resource, so that filters work correctly and don't result

      // in unnecessary dither.

      $resource = image_gd_create_tmp($image, $image->info['width'], $image->info['height']);

      if ($resource) {

        imagecopy($resource, $image->resource, 0, 0, 0, 0, imagesx($resource), imagesy($resource));

        imagedestroy($image->resource);

        $image->resource = $resource;

      }

    }

    return (bool) $image->resource;

  }

  return FALSE;

    // Find out if a transparent color is set, will return -1 if no

    // transparent color has been defined in the image.

      // Find out the number of colors in the image palette. It will be 0 for

      // truecolor images.

      $palette_size = imagecolorstotal($image->resource);

      if ($palette_size == 0 || $transparent < $palette_size) {

        // Set the transparent color in the new resource, either if it is a

        // truecolor image or if the transparent color is part of the palette.

        // Since the index of the transparency color is a property of the

        // image rather than of the palette, it is possible that an image

        // could be created with this index set outside the palette size (see

        // http://stackoverflow.com/a/3898007).

        $transparent_color = imagecolorsforindex($image->resource, $transparent);

        $transparent = imagecolorallocate($res, $transparent_color['red'], $transparent_color['green'], $transparent_color['blue']);

        // Flood with our new transparent color.

        imagefill($res, 0, 0, $transparent);

        imagecolortransparent($res, $transparent);

      }

      else {

        imagefill($res, 0, 0, imagecolorallocate($res, 255, 255, 255));

      }