Resp Images Find strings in string, order independent.

resp.php

// original HTML, when added to post
<img src="http://boilerplate.dev/wp-content/uploads/2015/03/spiral_01.jpg" alt="spiral_01" width="993" height="1000" class="alignnone size-full wp-image-45" />

// when change the class, order of HTML is changed.
<img class="alignnone wp-image-45 size-full" src="http://boilerplate.dev/wp-content/uploads/2015/03/spiral_01.jpg" alt="spiral_01" width="993" height="1000" />

Need to get: 

1. class
  i. the number 45 from the end of wp-image-45
  ii. the full class e.g. alignnone wp-image-45 size-full
2. the height
3. the width

So far I have : 

// this gets the whole of the image tag e.g. '<img src="http://boilerplate.dev/wp-content/uploads/2015/03/spiral_01.jpg" alt="spiral_01" width="993" height="1000" class="alignnone size-full wp-image-45" />'
preg_match_all( "/<img (.*?)\/>/", $content, $matches );

foreach ( $matches[0] as $key ) {
	// gets the width
	preg_match( '/(.*?)width=\"((\d+))\"(.*?)/', $key, $width );
	
	// gets the height
	preg_match( '/(.*?)height=\"((\d+))\"(.*?)/', $key, $height );
	
	// gets the class
	preg_match( '/(.*?)class=\"((.*?)wp-image-(\d+)(.*?))\"(.*?)/', $key, $class );

	$id = $class[4];
	$output_class = $class[2];
	$height = $height[2];
	$width = $width[2];

	// the string with <img>
	$img = $key;

	// string with <img srcset>
	$resp_img = es_get_output_resp_image( $id, $output_class, $max_width, true, $width, $height );

	// replace <img> with <img srcset...>
	$content = str_replace( $img, $resp_img, $content );
}