I don't mean to point out the obvious but you have already posted images, protected by copyright, online... in this forum.
You'll need to speak to an attorney regarding copyright and derivative works. A forum of strangers is not the best place to get legal advice.
I always imagined comic books as being drawn on paper and then scanned into Photoshop, or drawn directly with a digital tablet. I don't recall reading any photo montage comics when I was a little one.
Well, there is such a thing as photo comics, called fumetti comics. I think it's the new thing out. I was told this at the New Dimension Comics store at the local shopping mall (5 miles from our house) back in 2008. I shop there occasionally to buy comics, but most of them are cartoon-style, drawn comics, but occasionally you'll see a photo comic there for sale. Ok, shall I delete these images? And about this legal advice and the attorney - are there any free online forums (like there are computer advice and PC game advice, etc. forums) where I can register for free and discuss these matters as copyrights, comics, game/movie screenshots, editing, etc for free like I do on these gaming and computer forums that I currently belong to?
Regarding not remembering photo comics when "you were a little one," you're how old? I'm 58 years old, and I, too, only remember reading hand-drawn comics. AFAIK, the first photo comic I ever saw, I think, was around 2007 or 2008.
EDIT - Hey, I can't believe it -- I found a legal advice/attorney forum online! They exist!!!
Check it out, could you please?
The idea of suggesting an attorney is that it is very difficult to understand specifically what is involved here. There's no indication of the legal jurisdiction in which you live (and which laws apply), to what extent you will be using the images of others, and if any of your work is considered 'parody' and exempt from some copyright protection.
To keep things simple, in regard to copyright litigation, many artists choose to create entirely original art.
Most movies copyright notice say that they cannot be reproduced in any form, even parts of it. You clearly did not ask the right to reproduce the images, so they will have to be taken offline.
The way to create your comics legally is to take pictures yourself, or create them by hand.
As an alternative, you could look for Creative Commons, that allow derivative work images/films or Public Domain Photos/Videos. (most Photos from the US governement, but I don't remember if they allow derivative or commercial works)