Wordpress - Filter to remove image dimension attributes?

Thanks all!

The image_send_to_editor filter was the one I was looking for... thanks @t31os for pointing it out.

Here's my functions now.

add_filter( 'post_thumbnail_html', 'remove_thumbnail_dimensions', 10 );
add_filter( 'image_send_to_editor', 'remove_thumbnail_dimensions', 10 );

function remove_thumbnail_dimensions( $html ) {
    $html = preg_replace( '/(width|height)=\"\d*\"\s/', "", $html );
    return $html;
}

This removes inline dimension attributes from images retrieved with the_post_thumbnail(), and prevents those attributes from being added to new images added to the editor. Doesn't remove them from images retrieved through wp_get_attachment_image or other related functions (no hooks in there), but those cases can be processed in the templates files when necessary.

Modified this script a bit. Thanks for the help!

add_filter( 'post_thumbnail_html', 'remove_thumbnail_dimensions', 10 );
add_filter( 'image_send_to_editor', 'remove_thumbnail_dimensions', 10 );
// Genesis framework only
add_filter( 'genesis_get_image', 'remove_thumbnail_dimensions', 10 );
// Removes attached image sizes as well
add_filter( 'the_content', 'remove_thumbnail_dimensions', 10 );
function remove_thumbnail_dimensions( $html ) {
    $html = preg_replace( '/(width|height)=\"\d*\"\s/', "", $html );
    return $html;
}