MarkLidstone on "Adding Image to end of last line"

Hey Gang, maybe you can help me. I'm trying to add a tiny image to the end of the very last line of a post. I've got the function built so the image appears after each post, but my problem is, it appears on the next line and I can't for the life of my get it on the same line.

Here's my function

function new_default_content($content) {
global $post;
    if ($post->post_type == 'blog') {
    $content .= '<p class="sig"><img src="url/images/LM.jpg"  /></p>';
    }
    return $content;
    }
add_filter('the_content', 'new_default_content');

And I'm getting this type of result:

This is the end of the post
[image]

But I want

This is the end of the post [image]

Any help would be greatly appreciated. It's driving me bonkers.