code: func PasteCenter(background, img image.Image) *image.NRGBA {
  	bgBounds := background.Bounds()
  	bgW := bgBounds.Dx()
  	bgH := bgBounds.Dy()
  	bgMinX := bgBounds.Min.X
  	bgMinY := bgBounds.Min.Y
  
  	centerX := bgMinX + bgW/2
  	centerY := bgMinY + bgH/2
  
  	x0 := centerX - img.Bounds().Dx()/2
  	y0 := centerY - img.Bounds().Dy()/2
  
  	return Paste(background, img, image.Pt(x0, y0))
  }
docs: // PasteCenter pastes the img image to the center of the background image and returns the combined image.