Please note the sample image in the video is already black and white. All colour images will be printed as black and white with dithering, not grayscale. In case you missed it, here is a step by step guide from the video:
  1. Go to "Insert", "Picture" and "From File..."
  2. Find the image, select it and click "Open"
  3. Click and drag to move
  4. Drag a corner to resize while keeping the aspect ratio
  5. Drag an edge to stretch or compress the image
  6. Double click for more options