Images inside templates

I’m creating a template to add the featured image of each post inside the newsletter.

The problem is that the image is shown on the original size version and I want to add the thumbnail or a small size.

I have this template:

{{draw_line}} {{start_content}}

{{post_featured_image}}Categoria: {{search_reason}}{{post_title_with_perma_link}} {{post_content}}

{{end_content}}

This is the html for the repeater item:

<tr>
<td><!-- stc:This is the start of a repeatable content section -->{{start_content}}
<table class="content-table" style="width: 100%; max-width: 800px; border-collapse: collapse;">
<tbody>
<tr>
<td class="subscribeimg" style="width: 40%;">
<table width="100%">
<tbody>
<tr>
<td>{{post_featured_image}}</td>
</tr>
</tbody>
</table>
</td>
<td style="width: 60%; padding-left: 30px;">Categoria: {{search_reason}}<br />
<h2>{{post_title_with_perma_link}}</h2>
{{post_content}}</td>
</tr>
</tbody>
</table>
<!-- stc:This is the end of a (repeatable) content section -->{{end_content}}</td>
</tr>

I don’t know what I’m doing wrong… Anoyone can help me?

Thanks in advance