it ist not possible to use all the features of the noise-filter on a Bitmap, why?

Hello to all...most of the effects are not working on a Bitmap!? For example: i want to use the "noise"-effect on a Bitmap. I just can add noise, all the other possibilities (e.g."tune noise" or "Minimum" are disabled ( i cant click on them). This must be a stupid mistake of mine..Can anybody help, please? thanks a lot..