In 'The Five Doctors', why did Gallifrey appear to be like Earth?
As described in the episodes: 'The Sensorites', 'The Time Monster' and 'Gridlock', the grass is red; not green. The tress are silver; not green. The rocks are red, brown, purple and gold; not grey.
As seen in the episodes: 'The Invasion of Time', 'The Sound of Drums', 'The End of Time', 'The Name of the Doctor', 'The Day of the Doctor', 'Heaven Sent' and 'Hell Bent', the whole planet (including the sky and the landscape) is all brown, yellow, orange and red; not blue, green and grey.