In my app users are able to make a photo with camera. And I start it using intents:
You can't really change the things camera intent has to offer, and if you do find a device where the camera app would let you access the gallery I wouldn't depend on it.
I would recommend that whenever your user taps on the button or whatever launches the Camera Intent, launch a dialog that asks you the user to choose, "New Photo" or "Existing Photo". If they choose existing, launch the gallery intent.
Here is a really good tutorial for the gallery intent.