How to display loading image while actual image is downloading [duplicate]

Sometimes images take some time to render in the browser. I want to show a busy image while the actual image is downloading, and when the image is downloaded, the busy image is removed and the actual image should be shown. How can I do this with JQuery or any javascript?

Just add a background image to all images using css:

img {
  background: url('loading.gif') no-repeat;
}

You can do something like this:

// show loading image
$('#loader_img').show();

// main image loaded ?
$('#main_img').on('load', function(){
  // hide/remove the loading image
  $('#loader_img').hide();
});

You assign load event to the image which fires when image has finished loading. Before that, you can show your loader image.

I use a similar technique to what @Sarfraz posted, except instead of hiding elements, I just manipulate the class of the image that I'm loading.

<style type="text/css">
.loading { background-image: url(loading.gif); }
.loaderror { background-image: url(loaderror.gif); }
</style>
...
<img id="image" class="loading" />
...
<script type="text/javascript">
    var img = new Image();
    img.onload = function() {
        i = document.getElementById('image');
        i.removeAttribute('class');
        i.src = img.src;
    };
    img.onerror = function() {
        document.getElementById('image').setAttribute('class', 'loaderror');
    };
    img.src = 'http://path/to/image.png';
</script>

In my case, sometimes images don't load, so I handle the onerror event to change the image class so it displays an error background image (rather than the browser's broken image icon).

Instead of just doing this quoted method from https://stackoverflow.com/a/4635440/3787376,

You can do something like this:

// show loading image
$('#loader_img').show();

// main image loaded ?
$('#main_img').on('load', function(){
  // hide/remove the loading image
  $('#loader_img').hide();
});

You assign load event to the image which fires when image has finished loading. Before that, you can show your loader image.

you can use a different jQuery function to make the loading image fade away, then be hidden:

// Show the loading image.
$('#loader_img').show();

// When main image loads:
$('#main_img').on('load', function(){
  // Fade out and hide the loading image.
  $('#loader_img').fadeOut(100); // Time in milliseconds.
});

"Once the opacity reaches 0, the display style property is set to none." http://api.jquery.com/fadeOut/

Or you could not use the jQuery library because there are already simple cross-browser JavaScript methods.