Adding media support to a timeline plugin (WordPress)

I have installed this plugin -> http://wordpress.org/plugins/wordpress-posts-timeline/ .

With this plugin you can create a post and it displays in a timeline. My problem is that images don’t show when inserted in the post box.

I tried modifying the plugin code and put some get_attachment code inside the loop there but unfortunately didn’t work.. I can get all images to show, but not by ID of the post.

Youtube support would be nice too, but maybe that gets clear if this question is answered.

Current state -> http://erwin.my89.nl/stage/sieh

// Edit

I have tried alot of code with wp_get_attachment stuff.

<?php 
wp_get_attachment_image( $attachment_id, $size, $icon ); 
?>

&

<?php $uri = wp_get_attachment_image_src( $post->ID, 'medium' );
echo $uri[0];?>

But cant get it to work..

Thanks in advance.