How about a transformation option to choose width and height of inline images?

$transform_options = array ('string' => '<img src="transformation_wrapper.php3' . $options['wrapper_link'] . '" alt="[__BUFFER__]" width="' . (isset($options[0]) ? $options[0] : 320) . '" height="' . (isset($options[1]) ? $options[1] : 240) . '">');

Then the user puts, for example, '60','40' in the transform options.

Also I wonder how we could get the original width and height of the image, to display without distortion...

Marc