Well, I couldn't resist the lighthouse after all, but since I had turned the initial image into black and white, I thought I would try to emulate the original Macintosh display technique for grayscale photos. After black and white conversion, I changed the mode of the image to Indexed Color, set Colors to 3, the Palette drop-down to Uniform, unchecked Transparency and left Dither at Diffusion and Amount at 75%. Not every image works well with this technique, but the lighthouse did (with a little tweaking). The 'frame' is a three pixel white stroke with a bevel layer style.