Drupal 7.9 and flexible images Drupal 7.9 re-introduces height and width attributes to images - I understand this helps improve front-end performance, but it's giving me problems while using flexible images in the vein of responsive web design.

This is the same issue as whitefleaCH mentioned on this post: How can I prevent height/width attributes on images run through the theme system?

Using max-width in CSS still scales images, however the height remains as what was defined in the markup. Does anyone know how to either correct this in CSS or remove the height/width attributes from images all together?
Check out theme_image():

foreach (array('width', 'height', 'alt', 'title') as $key) {
  if (isset($variables[$key])) {
    $attributes[$key] = $variables[$key];
  }
}
return '&lt;img' . drupal_attributes($attributes) . ' /&gt;';


So you need to clean width and height as top level keys but also from the attributes array:

function mymodule_preprocess_image(&amp;$variables) {
  unset(
    $variables['width'],
    $variables['height'],
    $variables['attributes']['width'],
    $variables['attributes']['height']
  );
}


And yes, in Drupal 7, Variable process functions can now be used for all theming hooks. Don't forget to clear your cache so the new preprocess function is picked up.