Blurry Transparent Images
 

I frequently copy and paste bit map line drawings (similar to blue prints but
with a white background) into Excel. I like to make the white background
transparent so I can see the cells underneath. This used to work fine in
Excel 2003 however in Excel 2007, when I use the Recolor feature to set the
transparent color, the whole drawing becomes very blurry. Does anyone know
why this happens and any way to fix the problem? Thanks.