code: function()
  		{
  			if ( this.redoable() )
  			{
  				// Try to save. If no changes have been made, the redo stack
  				// will not change, so it will still be redoable.
  				this.save( true );
  
  				// If instead we had changes, we can't redo anymore.
  				if ( this.redoable() )
  				{
  					var image = this.getNextImage( false );
  					if ( image )
  						return this.restoreImage( image ), true;
  				}
  			}
  
  			return false;
  		}
docs: Perform redo on current index.