Grub4dos is able to mount superfloppy and hard disk type images - it is possible to boot Windows from either of these disk image formats. A hard disk type image contains a valid Master Boot Record (MBR) in the first sector of the disk and can contain multiple partitions. A superfloppy type image does not contain a MBR - the file system starts at the first sector of the disk and spans the whole of the disk.
Grub4dos expects disk images to comply with a C/H/S (Cylinder/Head/Sector) geometry. If the image conforms to LBA (Logical Block Addressing) mode only then Grub4dos will display errors whilst the image is mapped to memory, however the image may still boot.
Creating disk images compatible with Grub4dos (that do not display errors when mapped) involves a number of steps and calculations and can be complex. If you do not want to create your own images a selection is available for download here (all images have been formatted using compressed NTFS). Alternatively boot-land member oriensol has created an automated batch script for creating disk images - see here.
A table listing sizes (in sectors, MB's and GB's) for disks containing between 1 and 80 cylinders is available here. The information in this table can be used in conjunction with the methods detailed in the next pages of this guide to calculate the parameters required for manually creating a disk image (between 7.84 MB and 627.54 MB).