pamtotiff, pbmtowbmp, pnmtotiff, pnmtotiffcmyk, tifftopnm, wbmptopbm: add pages (#11408)

Co-authored-by: Sebastiaan Speck <12570668+sebastiaanspeck@users.noreply.github.com>

pages/common/tifftopnm.md

@@ -0,0 +1,20 @@
+# tifftopnm
+
+> Convert a TIFF image to a PNM image.
+> More information: <https://netpbm.sourceforge.net/doc/tifftopnm.html>.
+
+- Convert a TIFF to a PNM file:
+
+`tifftopnm {{path/to/input_file.tiff}} > {{path/to/output_file.pnm}}`
+
+- Create a PGM file containing the alpha channel of the input image:
+
+`tifftopnm -alphaout {{path/to/alpha_file.pgm}} {{path/to/input_file.tiff}} > {{path/to/output_file.pnm}}`
+
+- Respect the `fillorder` tag in the input TIFF image:
+
+`tifftopnm -respectfillorder {{path/to/input_file.tiff}} > {{path/to/output_file.pnm}}`
+
+- Print TIFF header information to `stderr`:
+
+`tifftopnm -headerdump {{path/to/input_file.tiff}} > {{path/to/output_file.pnm}}`