Loading gif align in the center of the page - html

Question

I am trying to make a loading gif to be on the center of the page also in mobiles.
Have tried
margin: 0 auto;
but i had no luck.
#bw-preloader, #bw-preloader:after {
background:url(http://i.imgur.com/ImksiyD.gif) !important;
background-repeat: no-repeat !important;
border-radius: 0% !important;
width: 256px !important;
height: 256px !important;
position: fixed !important;
top: 50% !important;
left: 50% !important;
margin: -50px 0px 0px -50px; !important;
}
#bw-preloader {
border: 0px !important;
-webkit-transition: opacity 10s !important;
position: fixed !important;
top: 50% !important;
left: 50% !important;
margin: -50px 0px 0px -50px; !important;
}
#media only screen and (max-width: 500px) {
#bw-preloader {
position: fixed !important;
top: 50% !important;
left: 50% !important;
margin: -50px 0px 0px -50px; !important;
}
}
You can see it live here
Could someone check it out if im missing something?
Also have tried
position: absolute;

Answer 1

This example code might help.
HTML
<div class="image-container">
<p class="image-holder">
<img src="loading.gif" />
</p>
</div>
CSS
div.image-container {
position: fixed;
top: 0;
left: 0;
right: 0;
width: 100%;
height: 100%;
bottom: 0;
background-color: #fff;
z-index: 999999;
text-align: center;
}
.image-holder {
position:absolute;
left: 50%;
top: 50%;
width: 30px;
height: 30px;
}
.image-holder img
{
width: 100%;
margin-left: -50%;
margin-top: -50%;
}
JS
$('div.image-container').delay(350).fadeOut('slow');

Answer 2

You need to adjust your CSS as follows:
#bw-preloader, #bw-preloader:after {
background: url(http://i.imgur.com/ImksiyD.gif) !important;
background-repeat: no-repeat !important;
border-radius: 0% !important;
width: 256px !important;
height: 256px !important;
margin: -128px 0 0 -128px;
}
You need to adjust the top and right margins by half the height and width respectively.

Answer 3

try the following:
position:absolute;
width:256px;
height:256px;
top:50%;
left:50%;
margin: -128px 0 0 -128px;
z-index:1000;
position absolute with the top:50% and left:50% move the elements left top part to the middle that is why you need to give it the negative margin of half the object witdht/height.
hope it helps