Something that's not getting published but might be useful if you have to work with .ima floppy backup images created using WinImage, rather than Linux-standard .img files that you can just mount as a device.
Do all of this as superuser.
List your loop devices:
losetup
If there's anything in this list, pick a loop device number that doesn't appear. I used 10.
If you don't already have a dedicated mount point for floppy drives:
mkdir /mnt/floppy
losetup /dev/loop10 ./disk.ima
mount -t vfat /dev/loop10 /mnt/floppy
I threw each disk of the sequence into a different loop device, and then sequentially mounted them on /mnt/floppy to swap disks in DOSBox.
You can also copy the mounted loop device to a more Linux-friendly img file, thus:
dd bs=512 if=/dev/loop10 of=image.img
Thanks to this person from 2008 who published the solution to their own question, thus saving me a lot of trial and error:
https://forums.fedoraforum.org/showthread.php?185346-How-to-deal-with-WinImage-ima-files-in-linux
Why yes, I am still making replacement floppy disks to replace dead ones in sets of installation media.
Back up your magnetic media while you still can.