[Techtalk] Convert colorimages into grayscale images

[Akkana]

Hamster writes:
> > Does anyone know a run-in-terminal program that I can use to convert
> > colorimages into grayscale images?
> 
> I think convert (from ImageMagick) is still the answer. 

ImageMagick is probably the best answer, but if some reason that
doesn't work, there's also (I did "apropos grey" to get this):

tiff2bw              (1)  - convert a color TIFF image to greyscale

from the libtiff package, which also includes utilities to convert
between tiff and other formats.

Netpbm is another useful package of command-line utilities to do
various image operations and convert between various formats.

Reading over that again, I remembered that most people spell it "gray",
so I did "apropos gray" and got a huge list (mostly netpbm utilities,
I think) which I'll paste here because it can be helpful to have
a specific program name to look up on rpmfind or google.

There are some really obscure image formats out there. :-)

asciitopgm           (1)  - convert ASCII graphics into a portable graymap
bioradtopgm          (1)  - convert a Biorad confocal file into a portable graymap
efix                 (1)  - convert between fax, text, bit-map and gray-scale formats
fstopgm              (1)  - convert a Usenix FaceSaver(tm) file into a portable graymap
hipstopgm            (1)  - convert a HIPS file into a portable graymap
jpegtopnm            (1)  - convert JPEG/JFIF file to portable pixmap or graymap
libpgm               (3)  - functions to support portable graymap (PGM) programs
pgm                  (5)  - portable graymap file format
pgmbentley           (1)  - Bentleyize a portable graymap
pgmedge              (1)  - edge-detect a portable graymap
pgmenhance           (1)  - edge-enhance a portable graymap
pgmhist              (1)  - print a histogram of the values in a portable graymap
pgmnoise             (1)  - create a graymap made up of white noise
pgmnorm              (1)  - normalize the contrast in a portable graymap
pgmramp              (1)  - generate a grayscale ramp
pgmslice             (1)  - extract one line of pixel values out of a portable graymap
pgmtexture           (1)  - calculate textural features on a portable graymap
pgmtofs              (1)  - convert portable graymap to Usenix FaceSaver(tm) format
pgmtolispm           (1)  - convert a portable graymap into Lisp Machine format
pgmtopbm             (1)  - convert a portable graymap into a portable bitmap
pgmtoppm             (1)  - colorize a PGM (grayscale) image into a PGM (color) image
ppmdist              (1)  - simplistic grayscale assignment for machine generated, color images
ppmtopgm             (1)  - convert a portable pixmap into a portable graymap
ppmtorgb3            (1)  - separate a portable pixmap into three portable graymaps
psidtopgm            (1)  - convert PostScript image data into a portable graymap
rawtopgm             (1)  - convert raw grayscale bytes into a portable graymap
rgb3toppm            (1)  - combine three portable graymaps into one portable pixmap
sbigtopgm            (1)  - convert an SBIG CCDOPS file into a portable graymap

	...Akkana