You can easily add images to your email templates or receipt templates in FormSnap. It's simply a matter of adding your desired image as a site resource in RapidWeaver, then use HTML image tags to present the image where you desire. You can't simply drag and drop an image in the template area because Rapidweaver is setup to build web pages with locally published resources) and not html emails. A little coding will get you there, it's easy.
Once your desired image has been added to Rapidweaver, view it in your resources list and you'll see the full path to the PUBLISHED file on the web. It will look something like:
Online Location: http://www.yoursite.com/resources/imagename.jpg
To insert this image in your template, you'd use a simple html image tag like this:
<img src="http://www.yoursite.com/resources/imagename.jpg" alt="" />
This will place the image in the email generated by FormSnap.