I would like to show at least one more example about how detailed Photo Sketch drawings can be. This tool is capable of generating really well calculated fine strokes.
You can choose among several drawing styles with different detail levels. When using it, if your input photo/image already has very well defined, high contrast regions, turn the "Use smart strokes" option off.
Below I show a photo and a pencil sketch created from it. You can click the images for a full size viewing. More examples can be seen at this Photo Sketch gallery.