Dew and hoarfrost accumulate on objects when there is more moisture in the air than the air can carry. If, when air is cooled down, it contains enough water to cause the dew point to be above freezing, then dew forms. But if the air is sufficiently dry that the dew point is below 0°C (32°F), then hoarfrost forms.
Hence, these pictures should show the formation of crystals on a subject. Pictures should not be just generally snowy scenes.
