documentclass{book}
usepackage{tikz}
usetikzlibrary{external}
tikzexternalize
usepackage[makeindex]{imakeidx}
makeindex[columns=3]
begin{document}
tikzsetnextfilename{testPdfFile}
Aindex{Test} simple tikz-image is here: tikz fill (0,0) circle(5pt);
printindex
end{document}