1. Log in to your dashboard--> layout- -> Edit HTML

2. Click on "Expand Widget Templates"

3. Search "Ctrl+F" and find the following cod:

<div class='blog-pager' id='blog-pager'>
<b:if cond='data:newerPageUrl'>
<span id='blog-pager-newer-link'>
<a class='blog-pager-newer-link' expr:href='data:newerPageUrl' expr:id='data:widget.instanceId &quot;_blog-pager-newer-link&quot;'
expr:title='data:newerPageTitle'><data:newerPageTitle/></a>
</span>
</b:if>

<b:if cond='data:olderPageUrl'>
<span id='blog-pager-older-link'>
<a class='blog-pager-older-link' expr:href='data:olderPageUrl' expr:id='data:widget.instanceId &quot;_blog-pager-older-link&quot;'
expr:title='data:olderPageTitle'><data:olderPageTitle/></a>
</span>
</b:if>

<b:if cond='data:blog.homepageUrl != data:blog.url'>
<a class='home-link' expr:href='data:blog.homepageUrl'><data:homeMsg/></a>
<b:else/>
<b:if cond='data:newerPageUrl'>
<a class='home-link' expr:href='data:blog.homepageUrl'><data:homeMsg/></a>
</b:if>
</b:if>

</div>

4. Replace the upper code with the next one:

<div class='blog-pager' id='blog-pager'>
<b:if cond='data:newerPageUrl'>
<span id='blog-pager-newer-link'>
<a class='blog-pager-newer-link' expr:href='data:newerPageUrl' expr:id='data:widget.instanceId &quot;_blog-pager-newer-link&quot;' expr:title='data:newerPageTitle'><img alt='Back Page' border='0' src='http://img696.imageshack.us/img696/4351/prev1.png?imgmax=800' title='pagina precedenta'/></a>
</span>
</b:if>

<b:if cond='data:olderPageUrl'>
<span id='blog-pager-older-link'>
<a class='blog-pager-older-link' expr:href='data:olderPageUrl' expr:id='data:widget.instanceId &quot;_blog-pager-older-link&quot;' expr:title='data:olderPageTitle'><img alt='Next Page' border='0' src='http://img214.imageshack.us/img214/4452/netol.png?imgmax=800' title='urmatoarea pagina'/></a>
</span>
</b:if>

<b:if cond='data:blog.homepageUrl != data:blog.url'>
<a class='home-link' expr:href='data:blog.homepageUrl'><img alt='home' border='0' src='http://img230.imageshack.us/img230/9030/homex.png?imgmax=800' title='Home'/></a>
<b:else/>
<b:if cond='data:newerPageUrl'>
<a class='home-link' expr:href='data:blog.homepageUrl'><data:homeMsg/></a>
</b:if>
</b:if>

</div>

5. Change the red links with your images links and then save the template.