We are trying to create a Custom HTML email template. We have followed the instructions from  "Creating HTML Email Templates". The problem is trying to add images to our new custom email template. We have loaded all of the images into a "Document" folder, however we don't know how to reference where these images are stored.

The example given is confusing.

<img src="https://na2.salesforce.com/servlet/servlet.ImageServer? id=015D0000000Dpwc&oid=00DD0000000FHaG&lastMod=1270576568000" alt="Company Logo" height="64" width="64"/>

What should we do to reference our specific images?

What folder should we upload the images to. We have a custom html template and all we need is to be able to upload the images (changing the "img src" will be easy once we know where that folder with images is) 

Thank you