<style type="text/css">
table table table td {vertical-align:top ! important;}
span.blacktext12 {
visibility:visible !important;
background-color:transparent;
background-image:url("http://i257.photobucket.com/albums/hh231/skyfire_above/leavesfallingextended.png");
background-repeat:no-repeat;
background-position:center center;
font-size:0px; letter-spacing:-0.5px;
width:435px; height:284px; display:block !important; }
span.blacktext12 img {display:none;}
</style>

<style type='text/css'>



.thumbnail{

position: relative;

z-index: 0;

}



.thumbnail:hover{

background-color: transparent;

z-index: 50;

}



.thumbnail span{ /*CSS for enlarged image*/

position: absolute;

background-color: black;

padding: 5px;

left: -100px;

border: 1px dashed gray;

visibility: hidden;

color: #FFFF00;

text-decoration: none;

}



.thumbnail span img{ /*CSS for enlarged image*/

border-width: 0;

padding: 2px;

}



.thumbnail:hover span{ /*CSS for enlarged image on hover*/

visibility: visible;

top: 0;

left: 10px; /*position where enlarged image should offset horizontally */



}



</style>

Después sólo nos faltará aplicar este otro en el sitio que queramos mostrarlo bien sea un post o en el -sidebar-:

<a class="thumbnail" href="#thumb"><img src="http://i81.photobucket.com/albums/j219/jgutierrezs/arbol-2.jpg" width="100px" height="100px" border="0" /><span><img src="http://i81.photobucket.com/albums/j219/jgutierrezs/arbol-2.jpg" /><br />Inseguridad</span></a>

.clearfix:after {
    content: ".";
    display: block;
    height: 0;
    clear: both;
    visibility: hidden;
}

.clearfix { display: inline-block; }

/* Hides from IE-mac \*/
* html .clearfix	{ height: 1%; }
.clearfix			{ display: block; }
/* End hide from IE-mac */

font-family: 'Stone Sans ITC TT','Gill Sans',tahoma,sans-serif;

/*------------------------------------------------------------------
Name Of CSS File
Last Updated:  Date Here

0. CSS RESETS

1. STYLING


2. HEADER 
	2.1. Top Menu Text
	

3. CONTENT AND BODY
	3.1 Put Sub Category Here
	

4. FOOTER
	4.1 Put Sub Category Here
		
		
5. MISC
-------------------------------------------------------------------*/



/* 0. CSS RESETS
---------------------------------------------------------------------
*/

body, address, blockquote, dl, ol, ul, li, form, fieldset, h1, h2, h3, h4, h5, h6, p, pre, object, embed {
	margin:0;
	padding:0;
}

fieldset, table {
	border:none;
}

table {
	border-collapse:collapse;
	border-spacing:0;
	overflow:hidden;
	word-wrap:break-word; /* will not validate IE only */
}

caption, th, td {
	text-align: left;
}

html { 
	font-size:100.01%; 
	height: 101%; /* forces scroll on short length pages */
}

body { 
	height:100%;
	font:62.5%/1.3 Arial,Tahoma,Geneva,Helvetica,sans-serif;
	background:#FFF;
}

address, h1, h2, h3, h4, h5, h6, li, p, pre {padding: .3em 10px .8em;}

.float_right {
	float:right;
}

.clear_left {
	clear:left;
}

.clear_both {
        clear:both;
}

html,body,div,span,applet,object,iframe,h1,h2,h3,h4,h5,h6,p,blockquote,pre,a,abbr,acronym,address,big,cite,code,del,dfn,em,font,img,ins,kbd,q,s,samp,small,strike,strong,sub,sup,tt,var,dd,dl,dt,li,ol,ul,fieldset,form,label,legend,table,caption,tbody,tfoot,thead,tr,th,td{margin:0;padding:0;border:0;font-weight:normal;font-style:normal;text-align:left;font-family:inherit;}table{border-collapse:collapse;border-spacing:0;}ol,ul{list-style:none;}q:before,q:after,blockquote:before,blockquote:after{content:"";}

dt, dd{
    border: 1px red dotted;
    display: inline;
}
dt {
    clear: left;
    float: left;
    width: 100px;
}
dd {
    display:block;
    float: none;
    margin-left: 100px;
}

css corner

/** rounded corners **/

/* curved */
.bl { background: url(../images/j_crn_bl_light.png) 0 100% no-repeat;}
.br { background: url(../images/j_crn_br_light.png) 100% 100% no-repeat;}
.tl { background: url(../images/j_crn_tl_light.png) 0 0 no-repeat; }
.tr { background: url(../images/j_crn_tr_light.png) 100% 0 no-repeat;}
.bt { background:url(../images/j_border.png) 0 0 repeat-x; }
.dl{ background:url(../images/mw_line_grey.png) 0 0 repeat-y;}
.dr { background:url(../images/mw_line_grey.png) 100% 100% repeat-y;}
.bb { background:url(../images/j_border.png) 0 100% repeat-x; }

/* header red background curved */



HTML 


<div class="bb"> <div class="dl"><div class="bl"><div class="dr"><div class="br"><div class="bt"><div class="tl"><div class="tr">
 
<!-- search -->
 		<span> Text here</span><br /><br />
 
                 text here text here  
 </div></div></div></div></div></div></div></div>

/*STANDARD COMMANDS 
=== === === === === === === === === === */
.clear {
clear:both;
}
.left {
float:left;
}
.right {
float:right;
}
.block {
display:block;
}
.inline {
display: inline;
}
strong {
font-weight: bold;
}
em {
font-style: italic;
}
.dull {
color: #999;
}
.dark {
color: #333;
}
.invalid {
color: #F00;
font-weight: bold;
line-height: 92%;
font-size: 85%;
}
.valid {
color: green;
line-height: 92%;
font-size: 85%;
}

html, body, div, span, applet, object, iframe,
h1, h2, h3, h4, h5, h6, p, blockquote, pre,
a, abbr, acronym, address, big, cite, code,
del, dfn, em, font, img, ins, kbd, q, s, samp,
small, strike, strong, sub, sup, tt, var,
b, u, i, center,
dl, dt, dd, ol, ul, li,
fieldset, form, label, legend,
table, caption, tbody, tfoot, thead, tr, th, td { margin:0;padding:0;border:0;outline:0;vertical-align:baseline;background:transparent;font-size:1em;font-weight:normal; }
ol, ul { list-style:none; }
blockquote, q { quotes:none; }
blockquote:before, blockquote:after,
q:before, q:after { content:'';content:none; }
:focus { outline:0; }
ins { text-decoration:none; }
del { text-decoration:line-through; }
table { border-collapse:collapse;border-spacing:0; }
html, body { height:100%; }
body { background-color:#fff;color:#444;font-family:'Lucida Grande', Helvetica, Arial, sans-serif;line-height:1em;font-size:12px; }