I made a lubuntu live stick with lubuntu 19.04 and added apps, folders, and files. It now uses about 22 GB on a 64 GB USB stick. I can create an image from it which uses 64 GB as well of course. So it fits perfectly on other 64 GB sticks but also uses 64 GB on a 128 GB stick as well and the remaining 64 GB can’t be used while I can’t duplicate it on a 32 GB stick at all. Is there a way to create an ISO so I can install my image on 32 GB or 128 GB sticks as well? I couldn’t find anything yet and would be really thankful for help!
I’m a teacher and I’d like my students to get to know and use Linux and not be so fixated on Windows. So I created the lubuntu stick with educational apps, worksheets, bookmarks, …
I don’t want to rely on 64GB sticks only but also would like to use others and I would absolutely love to install my assembly on a PC as well.
If you want to install your system in 32+ GB drives, all partiitons should reside within the first 32 GB. It is a good idea to have some margin for undersized drives (that are nominally 32 GB but actually somewhat smaller). Also watch out for the difference between Gibibyte (2^30) and Gigabyte (10^9).
The following link describes what you should think of in order to clone and after that expand and/or move partitions to take advantage of the whole drive (if bigger than 32 GB).
The question wasn’t about why you want to do this, but the process you’re using, i.e. how. If the response you got from @sudodus doesn’t help, answering that question would help us help you.