Changing Blog title to image on this theme

Im trying to change the blog title to an image. I looked at a couple of threads on how to do this by replacing the blog header with

<span>
/”><img src=”[image url]” alt=”<?php bloginfo(‘description’); ?>” />
</span>

on the theme im using I think I need to incorporate the image link into this

<title><?php
	 	$replacethese = array('[',']');
		$replacewith = array(' ',' ');
		echo str_replace($replacethese, $replacewith, get_bloginfo('title')); ?>

I tried $replacewith("<img src='www.****.jpg'>)
but this may be way off. Could someone lend a hand

Thanks