Edited Issue: Converting to pcx files ignores bit depth [1198]

I have a project that requires me to convert a jpg to a pcx image with a bit depth of 1. Basically a black and white image.

Here's what i'm doing.

```
Using image As New MagickImage("color.jpg")
image.Threshold(New ImageMagick.Percentage(60))
image.BitDepth(1)
image.Write("blackandwhite.pcx")
End Using
```

the resulting image is black and white with 2 colors only, but the bit depth is 24

if I change this line:
```
image.Write("blackandwhite.pcx")
```
to:
```
image.Write("blackandwhite.tif")
```
the color depth is saved properly as a tif, however this doesn't help me because I need a pcx file

I've attached screenshots of the image properties from IrfanView

Thanks