There is disclosed an image post-processing method for adjusting glossiness of a fixed toner image. The image post-processing method includes a glossiness control step of, with a non-contact heating device, heating a toner image fixed to a recording medium so as to reduce glossiness of the toner image. The non-contact heating device is configured to heat the toner image fixed to the recording medium to a temperature which reduces the glossiness of the fixed toner image.