How to place a figure/image next to TOC element

Here I use the feature of specifying a separate heading in the toc to add the graphic, via lap, if necessary.

documentclass{article}
usepackage{graphicx}
begin{document}
tableofcontents

noindenthrulefill

section{Normal section}

section[{llap{includegraphics[height=baselineskip]{example-image}%
  kern20pt}Left of section number}]{Left of section number}

section[{Right of title includegraphics[height=baselineskip]{example-image}}]%
  {Right of title}

section[{Right of page  numberhfillrlap{kern20ptincludegraphics%
  [height=baselineskip]{example-image}}}]{Right of page  number}
end{document}

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SUPPLEMENT

In response to comments about the use of chapter in the book class, and vertical alignment of the image, I provide an additional MWE:

documentclass[a4paper,openright]{book}
usepackage{graphicx}
DeclareRobustCommandaddimg[1]{llap{raisebox{-dpstrutbox}%
  {includegraphics[height=baselineskip]{#1} kern20pt}}}
begin{document}
tableofcontents

noindenthrulefill

chapter[addimg{example-image}Left of section number]{Left of section number}

chapter[addimg{example-image}Machines d'audit et processus MCO et MCS]{Machines d'audit et processus MCO et MCS}
end{document}