Color Transition

How can I start with a black and white photo (desaturated) and have it transition into a color photo?

Add the photo to your timeline, then duplicate the slide in the storyboard and add a dissolve transition. Now go to the first slide and reduce the saturation in the “Image” section of the options sidebar (http://take.ms/4ol04) to zero. now the black and white photo will fade into the coloured photo.

Your suggestion worked great. Thanks
WAF