I open up an image, don’t do anything to it and export it as a 16 bit Tiff onto desktop and the size is 194.7 MB. I convert the same image to black and white and export it and I get the same size. When I export the same image as a jpeg I get 26.1 MB, I then convert the same original image to black and white, export it as a jpeg it comes out only as 17.1 MB.