image automatically shrink

Your image widths are being set within your CSS file (styles.css) at around line 244 I can see this:

#header-area img, #content img, .comment img, .widget img {
    height: 81px; margin-top:-12;
    width: 200px;
}

The particular selector coming into play on the page you linked to is #content img. Try replacing it with this:

#header-area img, .comment img, .widget img {
    height: 81px; margin-top:-12;
    width: 200px;
}