As we explained in previous chapter, the simple, single-stroke NPR's are not very suitable for bitmap images and produce usually unusable results. In fact on most of the simple Presets the bitmaps have NPR switched off.
However, there are few advanced NPR preset styles (using multisample strokes) that are designed to work well on bitmaps.
Here is an example of Real Engraving preset that works well on both vector objects as well as bitmaps.
The Presets that are suitable for bitmaps have them already switched on (Apply to Bitmaps)
Tip: Fine Tune the image with the NPR Quick Adjust in Color & Texture Palette.