Find an image you want to work with and create a blank layer above it. In that layer, using black, paint the area you want to "pop". In this case it was the cat's eyes and nose. Deselect the "eye" on the original image layer. Make sure your top layer with blacked out area is active. Choose Edit, Define Pattern. Make a copy of your color layer and create a New document with it. Convert the color image in the new document to Grayscale (Image, Mode) then to Bitmap (Image, Mode, Bitmap) choosing Custom Pattern for the Method. Use pattern you just made. Convert back to Grayscale.
Copy grayscale image and paste it into original document over the color image. Choose the Overlay blending mode at the top of the Layers palette. Experiment with Opacity. Make sure Eye on blacked out layer is off.