The final working version in both browsers is as follow:

<STYLE>
#ImageSpecial
{
   Background-Image: url(Images/Special2_E.png);
   Width: 79px;
   Height: 59px;
   Position: Relative;
   Margin-Top: -59;
}

.ImageStore
{
   width: 79px;
   Height: 59px;
}
</STYLE>

<IMG SRC=Store/1-1000/00000042.jpg Class=ImageStore><DIV ID=ImageSpecial></DIV>

Basically, in order to avoid a bug in IE and have everything ok, the DIV should come after.