Make image fill div completely without stretching

Question

I have large images of varying dimensions that need to completely fill 240px by 300px containers in both dimensions. Here is what I got right now, which only works for one d

Answer 1

This could do the job:

.container {
    float: left;
    height: 300px;
    width: 240px;
    background-color: red;
    margin: 20px;
}

img {
    width:240px;
    height:300px;
}