todonotes package with includegraphics produces compiling error

Question

I want to use the todonotes-package with a \includegraphics[]{}-command. It works well with text and also with the graphic but nevertheless I get two errors after compiling:

1. Argument of \reserved@a has an extra }.

   \par l.9 ...includegraphics[scale=1.3]{grafik/example}} I've run across a }' that doesn't seem to match anything. For example,\def\a#1{...}' and \a}' would produce this error. If you simply proceed now, the \par' that I've just inserted will cause me to report a runaway argument that might be the root of the problem. But if your }' was spurious, just type2' and it will go away.

2. Runaway argument?

   {@firstoftwo {\Gin@cliptrue \Gin@i }}\def \reserved@b {\Gin@clipfalse \ETC. ! Paragraph ended before \reserved@a was complete. \par l.9 ...includegraphics[scale=1.3]{grafik/example}} I suspect you've forgotten a `}', causing me to apply this control sequence to too much text. How can we recover? My plan is to forget the whole thing and hope for the best.

So it tells me that I have an extra } and a missing } at the same time? In fact the output pdf is ok but anyway, I would like to know how to avoid the errors. Is there perhaps an alternative way to achieve the comments with a picture on the side of the page?

\documentclass{article}
\usepackage[colorinlistoftodos,prependcaption,textsize=footnotesize,color=black!20,linecolor=black!20,bordercolor=white,backgroundcolor=white]{todonotes}
\usepackage{tikzducks}

\begin{document}

One morning, when Gregor Samsa woke from 
\todo{hallo} 
troubled dreams, he found himself transformed in his bed into a horrible vermin. He lay on his armour-like back, and if he lifted his head a little he could see his brown belly, slightly domed and divided by arches into stiff sections. The bedding was hardly able to cover it and seemed ready to slide off any moment. His many legs, pitifully thin compared with the size of the rest of him, waved about helplessly as he looked. "What's happened to me?" he thought. It wasn't a dream. His room, a proper human room although a little too small, lay peacefully between its four familiar walls. 
\todo{\includegraphics[scale=.3]{example-image}}
A collection of textile samples lay spread out on the table - Samsa was a travelling salesman - and above it there hung a picture that he had recently cut out of an illustrated magazine and housed in a nice, gilded frame. It showed a lady fitted out with a fur hat and fur boa who sat upright, raising a heavy fur muff that covered the whole of her lower arm towards the viewer. Gregor then turned to look out the window at the dull weather. Drops 

\end{document}

The complete log is:

This is XeTeX, Version 3.14159265-2.6-0.999991 (TeX Live 2019/Arch Linux) (preloaded format=xelatex 2020.2.10)  7 MAR 2020 21:31
entering extended mode
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Document Class: article 2019/08/27 v1.4j Standard LaTeX document class
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File: size10.clo 2019/08/27 v1.4j Standard LaTeX file (size option)
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\abovecaptionskip=\skip41
\belowcaptionskip=\skip42
\bibindent=\dimen102
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ABD: EveryShipout initializing macros
! Argument of \reserved@a has an extra }.
<inserted text> 
                \par 
l.10 ...\includegraphics[scale=.3]{example-image}}

I've run across a `}' that doesn't seem to match anything.
For example, `\def\a#1{...}' and `\a}' would produce
this error. If you simply proceed now, the `\par' that
I've just inserted will cause me to report a runaway
argument that might be the root of the problem. But if
your `}' was spurious, just type `2' and it will go away.

Runaway argument?
{\@firstoftwo {\Gin@cliptrue \Gin@i }}\def \reserved@b {\Gin@clipfalse \ETC.
! Paragraph ended before \reserved@a was complete.
<to be read again> 
                   \par 
l.10 ...\includegraphics[scale=.3]{example-image}}

I suspect you've forgotten a `}', causing me to apply this
control sequence to too much text. How can we recover?
My plan is to forget the whole thing and hope for the best.

File: example-image.pdf Graphic file (type pdf)
<use example-image.pdf>

Overfull \hbox (39.25674pt too wide) in paragraph at lines 10--10
[][][]  
 []

File: example-image.pdf Graphic file (type pdf)
<use example-image.pdf>

Overfull \hbox (39.25674pt too wide) in paragraph at lines 10--10
[][][]  
 []

[1

] (./name.aux) ) 
Here is how much of TeX's memory you used:
 12751 strings out of 492483
 265525 string characters out of 6134979
 355950 words of memory out of 5000000
 17018 multiletter control sequences out of 15000+600000
 3656 words of font info for 16 fonts, out of 8000000 for 9000
 1348 hyphenation exceptions out of 8191
 68i,12n,83p,977b,985s stack positions out of 5000i,500n,10000p,200000b,80000s

Output written on name.pdf (1 page).

Answer 1

The error is typical "fragile command in a moving argument" error, and LaTeX provides \protect for such situations.

I get the error in texlive 2018 but it goes if you use

\todo{\protect\includegraphics[scale=.3]{example-image}}
      %%%%%%%%%

In an updated texlive 2019 or in texlive 2020 pretest the original document as in the question gives no error.