It needs to be a spot colour image.
your monotone options are: eps, psd, or raw file formats.
who needs a monotone jpeg or tiff? do they know that such a thing doesnt exist?
Actually, QuarkXPress has had the ability to colorize both grayscale and bitmap TIFF files for as long as I can remember. I use this feature all the time, as it is far more efficient than having to recreate the files in Photoshop if the color has to be changed.
BTW, if you are going for print reproduction, it should be a TIFF (or EPS) file, not JEPG.
Neil
...or JPEG for that matter!