Here is an actual practical example of how to use what this vague page is talking about:
Not sure if this is best practice or whatever but it worked for me.
First, I had to define a variable with the wp_upload_dir function. Calling the wp_upload_dir function gives you the ability to call a bunch of different variations of paths to the uploads directory.
$image_path = wp_upload_dir();
This is where that link didn't help because I am really a php modifier not a php programmer. I ended finding out that all this stuff:
[path] => /home/example.com/wordpress/wp-content/uploads/2008/11
[url] => http://www.example.com/wordpress/wp-content/uploads/2008/11
[subdir] => /2008/11
[basedir] => /home/example.com/wordpress/wp-content/uploads
[baseurl] => http://www.example.com/wordpress/wp-content/uploads
meant that you have to take your variable with the wp_upload_dir and add an array that looks something like this:
this will now make this dynamically pull the upload url for whatever post you are dealing with:
<img src="<?php echo $image_path['url']; ?>/image.jpg" />
Hope this helps more than a link reference.