Please note that the problem is not white
color. It is because it is being transparent.
When an element is made transparent, all of its child element's opacity; alpha filter in IE 6 7 etc, is changed to the new value.
So you cannot say that it is white!
You can place an element above it, and change that element's transparency to 1
while changing the image's transparency to .2
or what so ever you want to.