Q: Importing And Editing Hi-Res Photos on iPhone 6

Hi Tanya,

Thanks for coming to us in the Apple Support Communities for support. I know it's nice to be able to manage photos on the go, and sync them the way that works best for you, so I'll be happy to provide some resources to help with this.

For your first point, it seems you are curious about moving these images to your iPhone and then exporting the edits. Below is an article regarding getting the photos onto your iPhone, and then another one that covers some details about exporting the edits that may help.

iTunes 12 for Mac: Add photos to iPod, iPhone, or iPad

What to expect when you import edited photos from your iPhone, iPad, or iPod to your Mac or PC

In order to import these photos onto your computer without using iPhoto, you can instead use Image Capture:

Image Capture: Transfer images and other items from your device

Regarding your photos going missing from iPhoto on your Mac, it sounds as though you may be using iCloud Photo Library to sync your photos. When you make a change on one device, that change is reflected on all devices using iCloud Photo Library with the same account. You can see more details about that service here:

iCloud Photo Library FAQ

I hope this helps clarify some of the questions you had! Cheers!