<p>I'm using ASP.NET Web Forms for blog style comments.  </p>

<p>Edit 1: This looks way more complicated then I first thought.  How do you filter the src?<br>
I would prefer to still use real html tags but if things get too complicated that way, I might go a custom route.  I haven't done any XML yet, so do I need to learn more about that?</p>

Use an XML parser to validate your input, and drop or encode all elements, and attributes, that you do not want to allow. In this case, delete or encode all tags except the
```
<img>
```
tag, and all attributes from that except
```
src
```
, alt
```
and title
```
.