Can this be done, say, if I wanted to burn a DVD image file and I don't have a DVD-RW drive?

Yup.  can be done.   The app I use for really big files snips a copy of the original into pieces of some fixed size -- lets say 700 MB

Then you've got part1, part2, part 3.

In reverse, you copy part 1, 2  & 3 to your hard drive and using good ol' DOS copy command in binary mode:

copy /B part1+part2+part3  destination_file  

and it puts them back together.

Here, read this:

JoneSoft File Splitter v1.6.0 (16 February 2002)
Written by Jaesen Jones
(c) 1998-2002 JoneSoft

web: www.ozemail.com.au/~jaesenj/software/software.html
email: [email protected]

"Another File Splitter program. However, this one is different
in the fact that it's free (for most users) and that it includes
all the features that most others leave out. You can split files
to any size you wish. Restoring is simply a matter of running
the restore (BAT) file created when the file is split, or, for
total control, you can restore using the File Splitter program.
Integrated with Windows Explorer to allow even more
flexibility. Full install/uninstall support."

LICENSE AGREEMENT
You should carefully read the following terms and conditions
before using this software.  Your use of this software
indicates your acceptance of this license agreement.

LICENSE
- This License Agreement (the "Agreement") is a legal
agreement between you, the end-user, and Jaesen Jones.
By using this software or storing this program on a computer
hard drive (or other media), you are agreeing to be bound by
the terms of this Agreement.

- Home users and non-profit organisations may install this
program and use it FREE for UNLIMITED time. Although not
a requirement, a postcard from your home town sent to the
address listed in "REGFORM.TXT" would be appreciated.

- Commercial users, profit, and government organisations
may install this program and use it free for THIRTY
CONSECUTIVE days. Continued use will require
registration. Please refer to "REGFORM.TXT" for details.

- This software may be distributed freely on online services,
bulletin boards, or other electronic media as long as the files
are distributed in their entirety.

- This software may not be distributed on CD-ROM, disk, or
other physical media for a fee without the permission of
Jaesen Jones.

- You may not alter this software in any way, including
changing or removing any messages or windows.

- You may not decompile, disassemble or reverse-engineer
this software.

COPYRIGHT
JoneSoft File Splitter is Copyright 1998-2002, JoneSoft. You
must treat the Software like any other copyrighted material.

DISCLAIMER OF WARRANTY
THIS SOFTWARE AND THE ACCOMPANYING FILES ARE
SUPPLIED "AS IS" AND WITHOUT WARRANTIES AS TO
PERFORMANCE OF MERCHANTABILITY OR ANY
OTHER WARRANTIES WHETHER EXPRESSED OR
IMPLIED. NO WARRANTY OF FITNESS FOR A
PARTICULAR PURPOSE IS OFFERED.

RELEASE NOTES
1.6.0
- Corrected "Integer Overflow" error when free space on
 destination drive is greater than 4GB
- Installation now points to correct filename
- Improved error handling and messaging
- Now supports restore direct from source (no need to copy
 to destination first unless using .BAT file)
- Minor code tweaks to improve performance

1.5.0
- Can now split and restore files up to 4GB
- Major code tweaks to improve performance
- Interface enhancements
- Improved folder selection handling
- Improved exception testing
- Implemented HTML Help

1.4.0
- Now successfully splits to any writeable media with enough
 free space
- Help file added

1.3.0
- Now displays the size of the file to be split and the number
 of split files that will be created (plus system files)
- Configuration added: allows default split to and restore to
 folders to be set and customised default split sizes
- Better conversion of KB to bytes for determining split size

1.2.0
- Web page and email address links now work under
 Win NT4.x
- Various code tweaks to improve performance

1.1.1
- Corrected BAT file to work with long file names with spaces

1.1.0
- Provided full install and uninstall support
- Context menu support in Windows Explorer ("Send To")
 added
- ".SPLIT" file extension now registered

1.0.2
- Now displays correctly when viewed under "Large font"
 setting

1.0.1
- Removed "About.wav" to save space and make program
 more compact

1.0.0
- Initial release