Hmm, I found it.
$architectNoScaleImages = array('wp-smiley', 'sociable-hovers', 'rating_title', 'icon', 'rating', 'podcasticon', 'site-icon', 'sociable', 'sociablefirst');
I'm not sure what to say the class is. Its just a regular image that is small. I'm not uploading a large image and then using the WP thumbnail. I'm just uploading small images. Can't you just make large images scale to fit? I have tried almost every mobile plugin and none that I remember do what this one does with small images.
Let me know how to find the class as I don't see anything special on any of my images. This is a normal smaller one:
[caption id="attachment_2514" align="aligncenter" width="135" caption="Fancy Topiary"]<img class="size-full wp-image-2514 " title="fancytopiary_gift" src="http://farmvillefanatic.com/blog/wp-content/uploads/2010/03/fancytopiary_gift.png" alt="" width="135" height="157" />[/caption]