An image in the middle of the category band

[MetalORock]

As a good to render comprehensible me, i have make two images (before/after)

The problem is to put an image over the bottom image

I've try some solutions but either that jumped a line, or very shifted towards left/right

Thank you in advance for your assistance and your councils !

Useful infos

Css of .tcat :

.tcat
{
background: #000000 url(http://www.metalorock.com/v2/images/greenfox/gradients/gradient_tcat.gif) repeat-x top left;
color: #FFFFFF;
font: bold 9pt verdana, geneva, lucida, 'lucida grande', arial, helvetica, sans-serif;
}

And codes it concerning the band of category, being in "forumhome_forumbit_level1_nopost" :

<td class="tcat" colspan="<if condition="$vboptions[showmoderatorcolumn]">6<else />5</if>">

*Sorry if my english is bad