NETPIC (Jim Tucker)
NETPIC is a DOS utility developed by Jim Tucker. Its main feature is to convert a GIF image file to a COM file that, when executed, displays the image.
Discussion
The generated COM file can optionally use an ASCII-only encoding suitable for inclusion in an email. See Executable envelopes#Transfer-encoded executables for other executable formats of this sort.
Early versions (pre-v1.3) have a -w option to encode an arbitrary COM file in an ASCII-only format. Later, this feature was moved to a separate NETRUN utility.
ASCII-encoded files are normally wrapped in some plain text instructions, telling you to use a text editor to save the payload data to a .COM file. Most versions have a -z option to omit the wrapper, producing a file that can be executed directly (though you may have to rename it to end in ".COM").
Versions 2.00+ include an NPX2GIF utility that converts an executable image file back to a GIF file.
Versions with the -w option also have a -e option, to recover the original binary COM file from an ASCII-encoded COM file.
Identification
(Based on limited research.)
Binary-encoded graphics files are observed to start with bytes f6 06 2f 01 ff 74 ?? ba 15 01 b4 09 cd 21 b4 07.
ASCII-encoded graphics files, without the wrapper, older 3→4 format, start with "NETPIC.COM" (which apparently is valid x86 machine code).
ASCII-encoded graphics files, without the wrapper, newer 4→5 format (default for v2.00+), start with "XPPPYZIQD". This does not distinguish them from NETSEND and some NETRUN files. Files made by NETPIC apparently have "NETPIC" at offset 47.
ASCII-encoded arbitrary COM files (-w option) start with "COM-PRG.COM". This does not distinguish them from older NETRUN files. Files made by NETPIC v1.0d have "NETPIC" at offset 520.
Software
- NETPIC v1.0d - Ambiguous version number -- also uses 1.0e. Claims to be the first release.
- NETPIC v3.20 - Includes a partial change log in the NETPIC.TXT file.
- NETPIC v4.20
