Does art keep its value after restoration?

You have probably heard of Cecilia Giménez, a 80 year old Spanish woman behind what has been called 'the worst restoration of art history'.
The case raised a number of questions in the art world and sparked a variety of reactions. Rana spoke eloquently of different theories that can help us identify art, such as the artist intent, the mastery of skills, aesthetic appreciation or the audience's reception.

We may therefore wonder if a work of art is still art after restoration and/or it is a completely new piece.