Hi!
I believe the best possible solution in this case is to force a transparent background by custom CSS. To make the icon background transparent use this:
[code].promagnifier {
background: transparent !important;
}[/code]
Also, note, that transparent in this case means, that the underlying layer gets displayed. If the color of the main container is not transparent, then it will still be colorized. If you wish, you can make that transparent as well:
[code].probox {
background: transparent !important;
}[/code]
I hope this helps!