Installing the GIMP FFT plugin (in Windows)

The short of it: to install the Fourier FFT transform plugin into GIMP, download the latest version from here (registry.gimp.org). (I chose the Windows distribution, 32 bits).

From this gimpchat.com forum post I learned that both fourier.exe and libfftw3-3.dll must be placed into the GIMP plugins folder (specifically
C:\Program Files\GIMP-2.0\lib\gimp\2.0\plug-ins).

Unfortunately, when starting GIMP again, I got the error that the file libgcc_s_sjlj-1.dll was not found, so this meant that the filter wouldn't work.

To get the libgcc_s_sjlj-1.dll file, this instruction on another GIMP plugin suggested how to get that file: download the x32-4.8.0-release-win32-sjlj-rev2.7z package from Sourceforge (36.1 Mb); then you need to open the compressed file with 7-Zip (if you don't have it, download and install it separately beforehand), move to directory x32-4.8.0-release-win32-sjlj-rev2.7z\mingw32\bin\, and there's the file.

Extract only libgcc_s_sjlj-1.dll to C:\Program Files\GIMP-2.0\lib\gimp\2.0\plug-ins .

I became interested in the FFT plugin from a Wikimedia Commons Help section offering instructions about image manipulation, introducing the plugin here and in the next section.