I downloaded this file at Bit Torrent. I suppose the movies format is "avi" or "mp4". You are right about ISO being a disk image. That's why it can only be burned in my case on a BD-R disk to view it.
As I mentioned this is 33 gig file downloaded to the computer. I'm not burning it from a disk or making a copy, hence your question; "How could you have a disk image of something bigger than a disk?".
My solution will be to use a 50 gig BD-R disk and burn it on on side (25gig) and the remainder (8gig)= 33 gig on the other side. Or use 2 one sided 25. My problem is that I don't know how to split this data or rather burn it as a continuation.
If I use Power2Go software it will tell me that the data will not fit. I don't want to waste a disk to trial and error. I don't know if at the end of the first 25gig burn the program will prompt me to insert another disk to finish the other 8gig or terminate at 25gig ignoring the remainder.
So I'm looking for some help from someone who has had experience in a case scenario like mine. Hope this clarifies some of your inquiries. Thanks for taking time to help.