Adjusting post width according to the image size

Question

I am building a theme for a comic site. It seems some images are bigger than the post size. I need to resize the images according to the Original Image size. Can I achieve this through CSS? It doesn't matter if it extends the screen-size and scrolling window is shown.

Answer 1

Markup:

<div class="post">
    <div class="thumbnail">
        <img class="thumb" src="http://placehold.it/950x450/" />
    </div>
</div>

CSS:

.post { 
    width: 500px;
}

.post img.thumb {
    width: 100%; /* fill available space of parent and keep aspect ratio */
}

Fiddle: http://jsfiddle.net/