Update: April 28th, 2005
We have just added a side by side image sample comparison between the Nikon D70 and the Nikon D70s taken at 400 ISO. See how the cameras compare here.
The general image quality from the Nikon D70s seems very similar to that delivered by the Nikon D70 (very good), which is what we expected given the two cameras share the same hardware technology.
Looking at the Nikon D70s image samples taken at high ISO settings (1000 ISO), we feel that the D70s does offer a slight improvement in noise suppression compared to the Nikon D70, a camera that is already a very good performer at higher sensitivity settings. Looks like Nikon has tweaked some of the image processing in this area.