Have you tried Image Capture? It's right there in Applications>Image Capture. Your iPhone should be listed as a device. If you select it you should be able to see the entire Camera Roll on your iPhone and you can drag and drop any photo/video to a folder (or desktop) on your Mac. It might ask you to unlock the device first.
Once a photo/video is archived you'll still have it and can delete it from the camera roll. However, there's no way to put a photo back in the Camera roll after it's been deleted.
Question: How do i get my mac to recognize pictures on my iphone? When I connect my phone to the Mac it doesn’t pull up the photos to import them so I can delete the photos off my phone.