In your global head, you should have a stylesheet created for your css.
In it you will need to place the following:
CODE
.shadowed img{
visibility:hidden;position:absolute;top:0
}
However, if you plan on using any images in any override for the name_WEBSITE, you will need to add this to EACH image:
CODE
<img src="image.gif" style="visibility: visible; position: relative;">