[HTML]<style type="text/css">
<!--
.CMenu {
Position: Relative;
Height: 24px;
Width: 140px;
Padding-Top: 4px;
Padding-Left: 28px;
Text-Align: Left;
Text-Decoration: None;
Color: black;
Font-Family: Tahoma;
Font-Size: 11px;
Border-Top: #ffffff 1px Solid;
Border-Bottom: 1px Solid;
Border-Left: 1px Solid;
Border-Right: 1px Solid;
}

.CMenu:hover {
Border-Top: blue 1px Solid;
Border-Bottom: blue 1px Solid;
Border-Left: blue 1px Solid;
Border-Right: blue 1px Solid;
Background-Color: #bfd1ee;
Color: red;
}

.CMenuFrame {
Width: 144px;
Border-Top: blue 1px Solid;
Border-Bottom: blue 1px Solid;
Border-Left: blue 1px Solid;
Border-Right: blue 1px Solid;
Background-Color:;
Padding-Top: 1px;
Padding-Bottom: 1px;
Padding-Left: 1px;
Padding-Right: 1px;
}

.CMenuImage {
Position: Absolute;
Left: 3px;
Top: 3px;
Width: 16px;
Height: 16px;
}
-->
</style>[/HTML]

devi modificare la classe CMenuFrame in:

[HTML].CMenuFrame {
Width: 144px;
Border-Top: blue 1px Solid;
Border-Bottom: blue 1px Solid;
Border-Left: blue 1px Solid;
Border-Right: blue 1px Solid;
Background-image: url(Percorso/della/tua/immagine); /*Qui, devi sostituire "background-color" con "background-image" */
Padding-Top: 1px;
Padding-Bottom: 1px;
Padding-Left: 1px;
Padding-Right: 1px;
}[/HTML]