/* This removes the built-in caption shortcodes, and replaces them with XHTML-compliant, valid code */
remove_shortcode( 'caption' );
remove_shortcode('wp_caption');

function img_caption_shortcode_self($attr, $content = null) {

	// Allow plugins/themes to override the default caption template.

	$output = apply_filters('img_caption_shortcode_self', '', $attr, $content);
	if ( $output != '' )
		return $output;
	extract(shortcode_atts(array(
												'id'	=> '',
												'align'	=> 'alignnone',
												'width'	=> '',
												'caption' => ''
											), $attr));

	if ( 1 > (int) $width || empty($caption) )
		return $content;

	if ( $id ) $id = 'id="' . $id . '" ';
		return ' <span ' . $id . 'class="wp-caption ' . $align . '" style="width: ' . (10 + (int) $width) . 'px">'. $content . '<span class="wp-caption-text">' . $caption . '</span></span>';
}

add_shortcode('wp_caption', 'img_caption_shortcode_self');
add_shortcode('caption', 'img_caption_shortcode_self');



//CSS NEEDED FOR THIS TO WORK PROPERLY
.wp-caption {
text-align: center;
padding-top: 4px;
}
.wp-caption img {
margin: 0 auto;
padding: 0;
border: 0 none;
}
.wp-caption .wp-caption-text {
display: block;
font-size: 11px;
line-height: 22px;
margin: 0;
padding: 0 3px 3px 0;
color: #fff;
text-align: center;
}