Is anyone else seeing that photos does not end up on the SD card?  While flying, and recording, when I take stills, the app makes the sound as if it is taking the shot, but I often end up with an SD card that has only 1 or 2 photos on it, when there should be plenty more.

What ad card r u using?

Seems to me a wrong card or a serious hardware problem...

Because of the resolution, you need a fast SD card. Are you using the one that came with the quad? Check PhantomHelp for cards, the faster, the better.

Are you recording video at the same time as trying to take photo's?

What Jayhkr said..  The P3 will not take photos while recording video, This came up a wee while ago...

Also, I have seen the odd corrupt image with the current firmware, normally the first or second image of a flight..  Not a big issue as I always take far more images than I need!

It happens to both the SD card that came with it, and a Sandisk Extreme.
I am recording video at the same time.  Sometimes I get a few photos that actually save, but most of the time I lose a bunch of them.
I tried while recording at 1080p as well as full 4K.