I am having a very frustrating time with my WDTV Live 3rd gen connected to a My Cloud 3TB via home network. While I have no problem seeing the photos on the My Cloud using network share, I have to manually advance to the next photo using the remote for some usability. Otherwise, the photo transition takes ages (anywhere between 20 secs to 2+ mins) once the play button is pressed. I am on the latest firmware and have enabled slideshow in options with a transition time of 3 seconds.
On a different note, while as a product, its greatest pro is the number of formats it supports, WD TV Live needs better implementation of features as many a time, it comes across as being clunky. A lot of feaures are hidden or dont work in a straightforward way and usability for non-tech savvy people is a big question mark.