Contain an image within a div?

Question

I want to contain an image into a 250 x 250 div, forcing the image to resize but not stretch. How can I do this? By the way, the image will usually be bigger than the div it

Answer 1

Since you don't want stretching (all of the other answers ignore that) you can simply set max-width and max-height like in my jsFiddle edit.

#container img {
    max-height: 250px;
    max-width: 250px;
} 

See my example with an image that isn't a square, it doesn't stretch