Graphic upload

Hi Experts,

I am facing one problem in signature upload. I am uploading signature of type bitmap in se78. And I am giving color option while uploading. It is giving problem in print I mean it is showing grey color in back ground of signature. Please tell me how to avoid grey color in back ground of signature any settings need to do? I tried 256 color bit map also. Please help me I will give points.

Thanks a lot in advance