The equivalent of creating a disk image from a folder like in macOS can be achieved in linux as well. You'll need the genisoimage package, which will install the mkisofs command. After that, you can easily create ISO files from a folder's contents. The additional flags, such as -J make the ISO Windows-compatibel.

mkisofs -J -l -R -V "Label CD" -iso-level 4 -o output.iso input_directory