[-valign={top|middle|bottom| above|below}] [-xoff=X] [-yoff=Y]
[-alpha=alpha-pgmfile] [-invert] [-opacity=opacity] overlay_file
[underlying_file [output_file]]

Minimum unique abbreviation of option is acceptable. You may use dou-
ble hyphens instead of single hyphen to denote options. You may use
white space in place of the equals sign to separate an option name
from its value.

This program is part of Netpbm.

pnmcomp was obsoleted by pamcomp,introducedwithNetpbm10.21 (March
2004). pamcomp is backward compatible with pnmcomp, plus adds many
additional functions, including the ability to process PAM images, and
tends to produce better transparency results.

pnmcomp remains in the Netpbm package because it may have fewer bugs
for now than pamcomp, and is in some environments faster (but newer
compilers have been seen to produce code for pamcomp significantly
faster than that for pnmcomp). Some day, pnmcomp will probably become
an alias for pamcomp.

You can use the pamcomp documentation for pnmcomp, considering the
following differences:

? pnmcomp options are a subset of pamcomp's, as

? pnmcomp always assumes the input is linear, as pamcomp

? pnmcomp cannot process PAM images.

netpbm documentation 15 February 2004 Pnmcomp User Manual(0)