How to resize an image to fit in the browser window?

sebnukem picture sebnukem · May 29, 2011 · Viewed 451.2k times · Source

This seems trivial but after all the research and coding I can't get it to work. Conditions are:

  1. The browser window size is unknown. So please don't propose a solution involving absolute pixel sizes.
  2. The image's original dimensions are unknown, and may or may not already fit the browser window.
  3. The image is vertically and horizontally centered.
  4. The image proportions must be conserved.
  5. The image must be displayed in its entirety in the window (no cropping.)
  6. I do not wish scrollbars to appear (and they shouldn't if the image fits.)
  7. The image automatically resizes when the window dimensions change, to occupy all the available space without being larger than its original size.

Basically what I want is this:

.fit {
  max-width: 99%;
  max-height: 99%;
}
<img class="fit" src="pic.png">

The problem with the code above is that it doesn't work: the pic takes all the vertical space it needs by adding a vertical scroll bar.

At my disposal is PHP, Javascript, JQuery but I'd kill for a CSS-only solution. I don't care if it doesn't work in IE.

Answer

sebnukem picture sebnukem · Feb 4, 2013

Update 2018-04-11

Here's a Javascript-less, CSS-only solution. The image will dynamically be centered and resized to fit the window.

<html>
<head>
    <style>
        * {
            margin: 0;
            padding: 0;
        }
        .imgbox {
            display: grid;
            height: 100%;
        }
        .center-fit {
            max-width: 100%;
            max-height: 100vh;
            margin: auto;
        }
    </style>
</head>
<body>
<div class="imgbox">
    <img class="center-fit" src='pic.png'>
</div>
</body>
</html>

The [other, old] solution, using JQuery, sets the height of the image container (body in the example below) so that the max-height property on the image works as expected. The image will also automatically resize when the client window is resized.

<!DOCTYPE html>
<html>
<head>
    <style>
        * {
            padding: 0;
            margin: 0;
        }
        .fit { /* set relative picture size */
            max-width: 100%;
            max-height: 100%;
        }
        .center {
            display: block;
            margin: auto;
        }
    </style>
</head>
<body>

<img class="center fit" src="pic.jpg" >

<script src="http://code.jquery.com/jquery-latest.js"></script>
<script type="text/javascript" language="JavaScript">
    function set_body_height() { // set body height = window height
        $('body').height($(window).height());
    }
    $(document).ready(function() {
        $(window).bind('resize', set_body_height);
        set_body_height();
    });
</script>

</body>
</html>

Note: User gutierrezalex packaged a very similar solution as a JQuery plugin on this page.