Nellie, this picture was indeed taken right before the anointing. If you look closely, you will see that the skirt of the linen gown for the anointing is pleated; it is different from the white tunic which is worn under the coronation robe and which is very flat and plain. I remember the anointing gown well from the coronation film. I have always loved the way the bodice was designed.

Edit: The anointing gown was removed before the Queen was dressed for the presentation of regalia and the crowning. In this video you can see the difference, between 5 and 6 minutes.

http://www.youtube.com/watch?v=aGLN1kREJ2Q