How to search for HTML tag within given string?
===

I know this may seem rather simple, but I am stumped on how to go about accomplishing this task. 

I need to remove all HTML IMG tags from an array key/value, then take those removed HTML IMG tags and push them back onto the same array, with it's own separate array key this time.

**Sample:**

    $array = array(
        'content' => '<img src="http://www.domain.com/images/img.png" width="100" height="100" alt="" />here is some content that might also be in this string.'
    );

    $array = array(
        'content' => 'here is some content that might also be in this string.',
        'image' => '<img src="http://www.domain.com/images/img.png" width="100" height="100" alt="" />'
    );

The HTML IMG tag and the rest of the text within the string will always be different. The content will never be exactly the same, so I don't really know how to go about doing this. I was thinking about `explode()` or `str_replace()`. 