She said they hadn’t been MADE in 20 years, not that this one was only 20 years old.
Or maybe they just have Polaroids.
We’ll probably never know. Because clearly George Lucas took Hurley’s script and changed some things (i.e. took out the “improvements” that Hurley made). Because, you know… whatever happened, happened…
Empire had no time travel in it. BTTF used a different model (ability to change timelines).
The Incident: Big Miles changes Baby Miles’ diaper, almost destroying the universe. 
I think the Incident, whoever causes it, will end up moving our time-shifted-to-the-70s Losties back to the fut… er… the present.
What about Ben’s mother?
The framed photos didn’t look like polaroids. But it’s ceratainly possible. The transcript is ambiguous:
Namaste transcript | Lostpedia | Fandom
I dunno, it’s possible. OTOH, they had the equipment to develop Ben’s X-rays.
In 2004, how difficult is it to have a photo printer?
I had one in my house at the time.
As for photos developed in the 70’s, it wouldn’t be shocking if Dharma had a dark room. There are obviously a lot of things they want to catalog.
In the alternative, they could have sent the film to the mainland for development.
True. They had the regular sub-runs then.
Or they just stuck a Polaroid down his throat.
Maybe his cancer x-rays came out of the black box like an Eggo from a toaster. I’m picturing the x-ray popping up with an AOL-styled “You got cancer!”
I think the dream/visions are different than the ghost/apparitions. The dream stuff appears to only one person at a time, while the ghosts are apparently actually “there.” The dream people dont act in tune with reality: Horace for instance is on a time loop, and Bloody Boone is total dream logic (scenes skipping around).
Developing and printing photos isn’t that difficult. You can do it in your bathroom. Dharma can certainly afford a small photo lab.