The number of bytes that make up an image is a function of data that is recorded. So, a scene of the sky without much details, will show less bytes than, let's say a scene that includes many trees with leaves. Your camera will estimate based on the choice of JPEG or RAW how many images are left to be taken. When you check your manual, Nikon has provided you with a matrix that shows the approximate # of images per size of card that will be recorded depending on your choice of image quality/size etc.
When people shoot RAW, the maximum of bytes are recorded. The remaining shots left should probably show less than when you have selected JPG Large Fine, assuming you compare it to the same size card. There's a choice to shoot compressed or regular <uncompressed> RAW, that will affect the images remaining as well.
I do not know the KM 7D, but if it's sensor has less MPs than the D200's 10 MPs, there's your answer.
There are no settings to change, unless you deliberately want to shoot lower quality/size jpg.
