twiglett - that painting thing is normal. I remember on a parenting course I went on a while back that one of the nursery teachers mentioned it as a standard "stage" 3-4 year olds go through where they want to cover all their pictures up with one colour paint. There was a developmental reason for "hiding" the pictures like that, but I've completely forgotten it at the moment, sorry!
She did say that it can be seen as quite upsetting, but that she would matter of factly say something like "oh, I've seen you've covered your picture over. You've used the entire page. There's not even room for me to write your name!"