Make an image width 100% of parent div, but not bigger than its own width

Just specify max-width: 100% alone, that should do it.

Found this post on a Google search, and it solved my issue thanks to @jwal reply, but I made one addition to his solution.

img.content.x700 {
  width: auto !important; /*override the width below*/
  width: 100%;
  max-width: 678px;
  float: left;
  clear: both;
}

With the above I changed the max-width to the dimensions of the content container that my image is in. In this case it is: container width - padding - boarder = max width

This way my image won't break out of the containing div, and I can still float the image within the content div.

I've tested in IE 9, FireFox 18.0.2 and Chrome 25.0.1364.97, Safari iOS and seems to work.

Additional: I tested this on an image 1024px wide displayed at 678px (the max width), and an image 500px wide displayed at 500px (width of the image).