Yeah, probably... There's some ifs and buts with how the .img files were made, and we'd need more details for that.
You'd first need to start with partitioning from a live USB or optical media. You'd then expand the .img files, one into each partition. If you need to, you'd have to have a UEFI partition. You'll need a minimum of two partitions, though maybe 3 - all with the appropriate flags.
Either way, you'd then boot into a live USB, picking one of them to chroot and install GRUB. That should use the os-prober functionality to find both OSes. If it doesn't, you'd have to edit GRUB manually. With enough work, you should be able to make it function.
There are almost certainly easier ways to go about this. Extract the data you want to keep from the .img files, do a clean installation, and import that data. Really, consider that idea.