[magick-users] How to create 4-bit grayscale bmp images?

[John Harragin]

Hi  I'm running convert using variations of the command...

convert /var/www/html/photos/cyclamin.jpg  -resize 320x160 -depth 4 -colorspace GRAY -type Grayscale /var/www/html/photos/cyclamin.bmp

But 
identify -verbose cyclamin.bmp |grep -i depth 
reports...
Depth: 8 bits


I also have an unrelated question of how to modify the above command to allow the aspect ratio to change so the entire original image is jamed into the new geometry.

Thanks,

John