just get the source code (instructions are at https://calibre.kovidgoyal.net/wiki/...ctionsforlinux
In the instructions, change the second line to
cd calibre && make plugins
That will compile the pictureflow plugin placing the output into the directory src/calibre/plugins. Just copy the files there into the calibre installation overwriting the existing ones (do a find or a locate to learn where the files to overwrite are on)
Note that for the compilation to succeed you may need to install the qt-dev and pyqt-dev packages.