How can I remove all images from a PDF?

I want to remove all images from a PDF file.

The page layouts should not change. All images should be replaced by empty space.

• How can this be achieved with the help of Ghostscript and the appropriate PostScript code?

I'm putting up the answer myself, but the actual code is by courtesy of Chris Liddell, Ghostscript developer.

I used his original PostScript code and stripped off its other functions. Only the function which removes raster images remains. Other graphical page objects -- text sections, patterns and vector objects -- should remain untouched.

Copy the following code and save it as remove-images.ps:

%!PS

% Run as:
%
%      gs ..... -dFILTERIMAGE -dDELAYBIND -dWRITESYSTEMDICT \
%                 ..... remove-images.ps <your-input-file>
%
% derived from Chris Liddell's original 'filter-obs.ps' script
% Adapted by @pdfkungfoo (on Twitter)

currentglobal true setglobal

32 dict begin

/debugprint     { systemdict /DUMPDEBUG .knownget { {print flush} if} 
                {pop} ifelse } bind def

/pushnulldevice {
  systemdict exch .knownget not
  {
    //false
  } if

  {
    gsave
    matrix currentmatrix
    nulldevice
    setmatrix
  } if
} bind def

/popnulldevice {
  systemdict exch .knownget not
  {
    //false
  } if
  {
    % this is hacky - some operators clear the current point
    % i.e.
    { currentpoint } stopped
    { grestore }
    { grestore moveto} ifelse
  } if
} bind def

/sgd {systemdict exch get def} bind def

systemdict begin

/_image /image sgd
/_imagemask /imagemask sgd
/_colorimage /colorimage sgd

/image {
   (\nIMAGE\n) //debugprint exec /FILTERIMAGE //pushnulldevice exec
  _image
  /FILTERIMAGE //popnulldevice exec
} bind def

/imagemask
{
  (\nIMAGEMASK\n) //debugprint exec
  /FILTERIMAGE //pushnulldevice exec
  _imagemask
  /FILTERIMAGE //popnulldevice exec
} bind def

/colorimage
{
  (\nCOLORIMAGE\n) //debugprint exec
  /FILTERIMAGE //pushnulldevice exec
  _colorimage
  /FILTERIMAGE //popnulldevice exec
} bind def

end
end

.bindnow

setglobal

Now run this command:

gs -o no-more-images-in-sample.pdf \
   -sDEVICE=pdfwrite               \
   -dFILTERIMAGE                   \
   -dDELAYBIND                     \
   -dWRITESYSTEMDICT               \
    remove-images.ps               \
    sample.pdf

I tested the code with the official PDF specification, and it worked. The following two screenshots show page 750 of input and output PDFs:

If you wonder why something that looks like an image is still on the output page: it is not really a raster image, but a 'pattern' in the original file, and therefor it is not removed.