The template is not aware of the email template that is calling it.
If your template needs to look differently based on the e-mail, you need to use 2 templates for 2 different emails.
I mean instead of using in both of them
{{layout handle="some_handle_here"}}
in both of them, you need to use in the section one something like this:
{{layout handle="some_other_handle_here"}}
and create the new layout handle in one of your layout files and use a different template file.
I think your proposed solution will work without editing template files in your theme. Below I have created a simple sample template for you to paste in a new template.
System > Transactional Emails > Add New Template
Paste this into Template Styles
body,td { color:#2f2f2f; font:11px/1.35em Verdana, Arial, Helvetica, sans-serif; }
Below is the whole template to paste in to Template Content.
<body style="background:#F6F6F6; font-family:Verdana, Arial, Helvetica, sans-serif; font-size:12px; margin:0; padding:0;">
<div style="background:#F6F6F6; font-family:Verdana, Arial, Helvetica, sans-serif; font-size:12px; margin:0; padding:0;">
<table cellspacing="0" cellpadding="0" border="0" height="100%" width="100%">
<tr>
<td align="center" valign="top" style="padding:20px 0 20px 0">
<!-- [ header starts here] -->
<table bgcolor="FFFFFF" cellspacing="0" cellpadding="10" border="0" width="650" style="border:1px solid #E0E0E0;">
<tr>
<td valign="top">
<a href="{{store url=""}}" style="color:#1E7EC8;"><img src="{{var logo_url}}" alt="{{var logo_alt}}" border="0"/></a>
</td>
</tr>
<!-- [ middle starts here] -->
<tr>
<td valign="top">
<h1 style="font-size:22px; font-weight:normal; line-height:22px; margin:0 0 11px 0;"">Thank you for subscribing to our newsletter.</h1>
<p>Below you will find your $5 coupon to use in store.</p>
<p><img src="[THE ABSOLUTE URL FOR YOUR IMAGE EG: http://www.melissastore.com/media/coupon.png" alt="$5 Off Coupon" title="Print This Email to Claim your Coupon In Store" /></p>
</td>
</tr>
<tr>
<td bgcolor="#EAEAEA" align="center" style="background:#EAEAEA; text-align:center;"><center><p style="font-size:12px; margin:0;">Thank you again, <strong>{{var store.getFrontendName()}}</strong></p></center></td>
</tr>
</table>
</td>
</tr>
</table>
</div>
Note the line that contains
<img src="[THE ABSOLUTE URL FOR YOUR IMAGE EG: http://www.melissastore.com/media/coupon.png" alt="$5 Off Coupon" title="Print This Email to Claim your Coupon In Store" />
You need to substitute the src with your own image's url in the above code. Upload the image using your FTP client.
Best Answer
For this case you need to
create a handler
and this handlerwill render the you phtml
( at local.xml at app/design/frontend/YOUR_PAackage/YOUR_template/layout) on html templatethen on email html template call handler
OR: Without call of handler:
call a block file without layout handler and ans parameter for
\ see more at Display line in transactional e-mail if payment method is