A little while ago Apple changed the way the video out functions. Once upon a time, just connecting the AV cable from the phone to the TV ported the pictures and movies directly. Now it only works if the application ports the audio and video out, a function no longer handled in the system files, according to the Apple store tech today.
It all depends on whether or not the app developer built in a TV out function. Most of them don't have this functionality. I used to use presentation software for business from my phone, to a projector or large screen TV. That no longer works. I used to be able to flip through my photo album and see all that on the TV screen, the audience could tell me which photo they wanted to view, click on that one and it fills the screen, go back to the albums, flip through about 500 photos on phone, all that was visible on the TV for the whole room to see. Can't do that any more. Now the only way you can view photos on the TV is to use their "slideshow" app, which doesn't allow any flexibility, or flipping through pictures. If you try to advance the slides manually you get kicked out of "slideshow" and the TV screen goes blank. Until Apple reverses this "development" there's no work-around available. Someone has to develop an app that will allow this functionality and include a TV out functionality in the app.
BTW, the app store tech said that the only way to mirror the screen of the iPhone on the TV is to buy the Apple TV box, which now has that mirror function. So, now for my business I will have to lug that box and a huge TV around with me everywhere I go to do my presentations! Sweet!