Aligning 4 split images from 1 image - css

Question

I am trying to align these four separate spliced images from an original image. I am doing this because each portion of the image has a separate link.
I have the images align. Now all I want to do is shrink the size of the images via width: #%;
For some reason this just isn't seeming to work.
Any help would be appreciated.
Here is a link to the CodePen: http://codepen.io/anon/pen/pvGgdp
.split,
.split2,
.split3,
.split4 {
display: inline-block;
margin: -2px;
}
.spliter {
margin-top: -3px;
}
<div class="splitWrapper">
<div class="split">
<a href="#">
<img src="http://i.imgur.com/Jnah8Y0.png" title="source: imgur.com" />
</a>
</div>
<div class="split2">
<a href="#">
<img src="http://i.imgur.com/mGftOCN.png" title="source: imgur.com" />
</a>
</div>
<div class="spliter"></div>
<div class="split3">
<a href="#">
<img src="http://i.imgur.com/ZooSwpU.png" title="source: imgur.com" />
</a>
</div>
<div class="split4">
<a href="#">
<img src="http://i.imgur.com/sMsHX14.png" title="source: imgur.com" />
</a>
</div>
</div>

Answer 1

You could use background images and assign them to the a tags. I have amended your codePen here > http://codepen.io/anon/pen/YPBwJX
However, it may be better to just use one image, and overlay transparent a-tags, set them to display block and then you don't have to worry about the image lining up! Anyways, please see the code below for the question asked =)
.splitWrapper {
width: 850px;
margin: auto;
}
a.split1 {
background: url('http://i.imgur.com/Jnah8Y0.png');
}
a.split2 {
background: url('http://i.imgur.com/mGftOCN.png');
}
a.split3 {
background: url('http://i.imgur.com/ZooSwpU.png');
}
a.split4 {
background: url('http://i.imgur.com/sMsHX14.png');
}
a.split{
width: 417px;
height: 300px;
float: left;
margin: 0;
padding: 0;
display: block;
background-size: 417px 300px;
}
.clear { clear: both; }
<div class="splitWrapper">
<div class="clear"></div>
</div>

Answer 2

I don't think you quite understand how % works in CSS. % means that percentage of the parent element. Also, for it to work, the parent element has to have a defined width. Here's the CSS changes you need:
.splitWrapper {
width: 100%;
}
.split, .split2, .split3, .split4 {
display: inline-block;
margin: -2px;
width: 25%;
}
.split img,
.split2 img,
.split3 img,
.split4 img {
max-width: 100%;
}
.spliter {
margin-top: -3px;
}
http://codepen.io/anon/pen/KwJVGQ
You'll need to adjust your margins accordingly. You should use percentage margins since you're working with percents. Just divide the width of the margin by the width of the element and multiply it by 100 to get your margin percentage.