Taking Desktop Screenshots

I was Googling around the other night looking for graphics
help and ran across this site where I learned about some
X stuff I didn’t even know was there on my box:

Useful Things You Can Do with FVWM

Example of dumping the root screen using xwd, part
of the X Window System included with OpenBSD:
xwd -root -out file

Example of displaying the dumped image with xwud,
again part of the X Window System:
xwud -in file

Example of dumping the root screen & outputting it to
jpg format using xwdtopnm and pnmtopng, both
included in the netpbm port/package:

xwd -root |xwdtopnm |pnmtopng > file.jpg

Example of converting an existing screenshot taken with
xwd, using xwdtopnm and pnmtopng:

xwdtopnm < file | pnmtopng > file.png
xwdtopnm < file | pnmtojpeg > file.jpg

Example converting a screenshot taken with xwd with
convert, part of the ImageMagick port/package:

convert file file.png
convert file file.jpg

Cheers!