If you go to your photos on your computer then you can change them there. I don't know if changing the file type makes them look any different, though. It really just depends on the quality based on how you took the image. Like if you take a screenshot from your computer, that comes out as .png. When you find DVD covers, etc. on the internet, they'll usually be .jpg.
Correct in fact, but not correct in the present. The voice-over was directed to the present day audience -- a break of the fourth wall. It is implied that it is HER GHOST speaking to us. Therefore, her use of BCE is neither correct nor incorrect. This is a work of fiction and fantasy. The concepts you are addressing really do not apply here.
Well, the fact that the entire film is fictional it really doesn't matter either way, does it? The writer is just doing what they think would be most believable to the general audience and to the target audience which are kids, who aren't really going to rage over the inaccuracies (which to be honest sounds like you are a little).
I just don't feel like going back and forth between chat and what I'm doing elsewhere at this time in the evening. Don't take this the wrong way, but when I say no just leave it at that. I don't have to be in chat if I don't want to. If you want to talk to anyone else then just take a chance and wait for someone to show up.