If you have a DOS (FreeDOS or MS-DOS, etc.) floppy disk image (.ima or .img), you can just directly add it to the E2B drive and it should boot correctly.
If you want to be able to modify the contents, you can use a program like
WinImage, or you could convert the image to a FAT32 .imgPTN file.
Using the E2B FreeDos image
E2B includes a FreeDOS disk image as \_ISO\DOS\MNU\Freedos288.IMA.gz.
If you boot to this, you can access and run small DOS programs directly from the E2B drive because the FreeDOS image also loads an NTFS driver and support (sort of!) for long-filename for FAT32.