Fit background image to div

I have a background image in the following div, but the image gets cut off:

 <div style='text-align:center;background-image: url(/media/img_1_bg.jpg);background-repeat:no-repeat;width:450px;height:900px;' id="mainpage" align="center">

Is there a way to show the background image without cutting it off?

You can achieve this with the background-size property, which is now supported by most browsers.

To scale the background image to fit inside the div:

background-size: contain;

To scale the background image to cover the whole div:

background-size: cover;

JSFiddle example

There also exists a filter for IE 5.5+ support, as well as vendor prefixes for some older browsers.

If what you need is the image to have the same dimensions of the div, I think this is the most elegant solution:

background-size: 100% 100%;

If not, the answer by @grc is the most appropriated one.

Source: http://www.w3schools.com/cssref/css3_pr_background-size.asp

You can use this attributes:

background-size: contain;
background-repeat: no-repeat;

and you code is then like this:

 <div style="text-align:center;background-image: url(/media/img_1_bg.jpg); background-size: contain;
background-repeat: no-repeat;" id="mainpage">