Ok let’s see :
Do you have a reset stylesheet? If not I strongly suggest you you grab one and paste it at the top of your stylesheet.
Speaking of which, make sure that both the div and the paragraph have the same dimensions in it.
What do you mean you are getting the path from wordpress? Because it shouldn’t matter, the image should be hosted on your server regardless, it’s only a matter of grabbing it’s url.
$(‘#testo’).hover("your functions here");
Hope it helps.