Street aret or vandalism?

"Who is it owns the right to make meaningful icons in our city spaces?  Is it the citizens themselves or global corporations?" ~ Dr Richard Clay: Tearing Up History

This painting is by two artists called Pichi and Avo.  Since 2007 they have been producing stunning street art, infusing classical figurative detail with surrealistic spray-can talent.  Their work adorns the streets of Valencia in Spain.  Pichi & Avo website

The Authorities call this vandalism and is therefore illegal.

Whereas the Authorities call this ("Hello Boys" billboard poster campaign for Wonderbra) corporate advertising and is therefore legal.

But what do you think?