A Linux distro I wish to use, probably only through a VM, offers me the options of Live DVD or a VM version. Both are ISO images. What have they done differently inside the ISOs? I suppose I'd go with the VM anyway, but without knowing what makes it different.
The VM version is supposed to be installed on a Virtual Machine. A Live DVD is designed to run from a DVD and uses special tricks for its temporary storage etc. It is designed not change the system (for running the Distro) that is running the live DVD.
The VM version probably has other optimizations and does have access to its own partitions etc. However without the actual distribution I cannot be sure whether there are other differences.