Are you managing your photos in iPhoto on the Mac or are they just in a folder in the file system? How did you "extract" them to the mac to begin with?
The new pictures you take with the phone will have to be imported from the phone to your computer like you did with the others (imagine your phone as a regular digital camera). Once the photos are on your mac with the others, the next time you sync, the photos will get transferred back to your phone, likely in the "Pictures" album.
Basically, a long way of saying that there isn't a way to directly do it without synchronizing to the computer.
Now, I'm not sure how the cloud stuff factors in, I do everything locally through iPhoto.
The iOS 8 Photos app is confusing because it blends pictures you have taken with the phone alongside ones that reside on your phone already Under the "Photos" category. The "Camera Roll" used to be the place to differentiate between the two (like an SD card in a digital camera"
And albums are basically like playlists in iTunes. Your photos aren't duplicated into to albums, they are just collected there. The "Recently Added" album is akin to a smart playlist in iTunes.
Not sure if anything here helps, but this is what I sorted out so far.