If all the images were captured on the iPhone, disabling My Photo Stream won’t remove any images. That’s because Apple limits iOS to the most recent 1,000 images. PJ in particular has over 1,300 photos in the Camera Roll on his iPhone, but his My Photo Stream has only 1,000 images. All new captures and imports on all connected devices with this feature enabled upload to iCloud and sync to all connected devices, whether as thumbnails or full-resolution images.
