Image doesn’t display in IE

Hi all. I’m a bit puzzled here. I recently fiddled with my site and added buttons on the sidebar to allow guests to view only Japanese or only English posts.

https://michaeldowney.net

In firefox the button images (flags) display correctly and I have a valid css stylesheet. However, in both IE 6 and 7 they are not visible, but bizarrely the links to them are showing (when you hover over them the cursor changes). So only the images are missing…

I’ve looked around on the internet for fixes and tried the position: relative and such, but to no avail. Any ideas what I need to do to correct the code for IE?

Here is the code in my stylesheet and sidebar:

Stylesheet:

#sidebar ul.language li {
display: inline;
}

#sidebar ul li.japanese a{
	padding: 0 0 20px 42px;
	background: url(images/jp.gif) no-repeat center 2px;
}

#sidebar ul li.english a{
	padding: 0 0 20px 37px;
background: url(images/gb.gif) no-repeat center 2px;
}

#sidebar ul li.normal a{
	padding: 0 0 20px 37px;
	background: url(images/gbjp.gif) no-repeat center 2px;
}

#sidebar ul li.syndicate a{
	padding: 0 0 20px 37px;
	background: url(images/feed.gif) no-repeat center 2px;
}

Sidebar code:

<ul class="language">
<li class="japanese"><a href="<?php echo get_category_link(7);?>" title="日本語"></a></li>
<li class="english"><a href="<?php echo get_category_link(12);?>" title="English" ></a></li>
<li class="normal"><a href="<?php echo get_settings('home');?>" title="English and Japanese"></a></li>
<li class="syndicate"><a href="<?php bloginfo('rss2_url'); ?>" title="<?php _e('Subscribe to this site using RSS'); ?>" class="feed"></a></li>

</ul>

Any help is much appreciated! I am not an expert on CSS and coding, but I have a little knowledge.