Review the classes called in:
<div id="content_pa">
<div id="attachment_40" class="wp-caption aligncenter" style="width: 211px">
<a href="http://mitomeru.net/wp-content/uploads/2011/11/pirezedmyolver_10.jpg">
<img class="size-medium wp-image-40" title="pirezedmyolver_10" src="http://mitomeru.net/wp-content/uploads/2011/11/pirezedmyolver_10-201x300.jpg" alt="" width="201" height="300" />
</a>
<p class="wp-caption-text">efwefevf43t35t</p></div>
The <div> uses class="wp-caption aligncenter"
While the <img> uses class="size-medium wp-image-40"
We see in the style sheet:
html,body,div,span,applet,object,iframe,h1,h2,h3,h4,h5,h6,p,blockquote,pre,a,abbr,acronym,address,big,cite,code,del,dfn,em,font,img,ins,kbd,q,s,samp,small,strike,strong,sub,sup,tt,var,b,u,i,center,dl,dt,dd,ol,ul,li,fieldset,form,label,legend,table,caption,tbody,tfoot,thead,tr,th,td {
font-size:100%;
}
So img only has font-size:100%;
remove img from that list and create a new one...if other images on your site will be affected by this (they will) create a new style:
.newstyle img {
align:center;
<-more css->
}
and call that in the post.