xwdtopnm
Convert an X11 or X10 window dump file to PNM.
TLDR
Convert a XWD image file to PBM
$ xwdtopnm [path/to/input_file.xwd] > [path/to/output_file.pnm]
Display information about the conversion process
$ xwdtopnm -verbose [path/to/input_file.xwd] > [path/to/output_file.pnm]
Display the contents of the X11 header of the input file
$ xwdtopnm -headerdump [path/to/input_file.xwd] > [path/to/output_file.pnm]
