- Select a virtual machine by clicking its name in the VirtualBox window
- Click the Machine menu at the top of the VirtualBox window, then click Settings
- Click the Storage category in the Settings window
- Right-click in the storage tree pane, and click Add Floppy Controller
- Right-click the Floppy Controller device, and click Add Floppy Drive
- Click the Choose Disk button in the prompt window that appears
- Navigate to the floppy disk image file (.IMG) on your computer and double-click it
If that doesn't work, try renaming the .IMG as .ISO and mount it.
If that too doesn't work, use VBoxManage's convertfromraw command as follows:
VBoxManage convertfromraw --format VDI [filename].img [filename].vdi
Mount the VDI as a hard disk.
