How do I save the image in an image control to a file on the disk in 256 color in BMP format? I used SavePicture method as folows

SavePicture img1.Image, "C:\test.bmp"

The problem is that, it saves the picture in 16 million colors.I cannot use images in 16 Million colors in my project, because I am specifically working with only 256 color bitmaps. Please help.