kikib on "Prev Post & Next Post Links as Images"

I looked at other topics on this problem but I wasn't able to make it work. Here's my code:

<div class="navigation">
<div class="nav-link prev"><?php previous_post('%','<img src="images/pagenavlinks.png" alt="Previous"','no'); ?></div>
<div class="nav-link all">All Projects</div>
<div class="nav-link next"><?php next_post('%','<img src="images/pagenavlinks.png"','no'); ?></div>
</div>

and CSS:

.navigation {
	float: left;
	position: relative;
	width: 100%;
	margin: 5px 0 10px 0;
	padding: 0 auto;
}
.navlink {
	float: left;
	width: auto;
	min-height: 1px;
	position: relative;
}
.navlink a {
	background: url(images/pagenavlinks.png) no-repeat scroll 0 0 transparent;
	border: 0 none;
	display: block;
	height: 30px;
	margin: 0 0 0 10px;
	padding: 0;
	text-align: left;
	text-indent: -9999px !important;
	width: 30px;
}
.navlink .prev a {
	background-position: 0 0;
}
.navlink .all a {
	background-position: -30px 0;
}
.navlink .next a {
	background-position: -60px 0;
}

The image is already called in the CSS but I'm not able to display it in my post "http://kikidesign.net/miele" and several others in portfolio page.