[Tex/LaTex] Why is “width=\textwidth” setting not properly scaling graphic

Question

I'm including a jpg figure in my LaTeX document like this:

\begin{figure}[htbp]\centering
    % fbox here only for illustrative purposes
    \fbox{\includegraphics[width=\textwidth,keepaspectratio]{Pictures/PoolofBethesda-CarlBloch}}
%   \includegraphics[width=\textwidth,keepaspectratio]{Pictures/LesNocesdeCana-PaoloVeronese}
    \caption{\emph{Healing at the Pool of Bethesda} (1883) by Carl Bloch.}
    \label{fig:Bethesda}
\end{figure}

However, the picture is not being properly scaled. I want the picture to be as wide as the text on the page with the aspectratio kept the same. I get this instead; you can see the box where the image should be:

If I simply replace the image with a different image (as shown in the commented line above) everything works as expected.

Why isn't my image being scaled properly? Am I missing something obvious?

The original image is this:

PS. I'm using the graphicx package with no options.

Answer 1

Just for a larger comment. This works just fine for me

\documentclass[a4paper]{memoir}
\usepackage{graphicx}
% I do not have that path on my PC
\graphicspath{{Pictures/}}
\begin{document}

\begin{figure}[htbp]
  \centering
  \includegraphics[width=\textwidth,keepaspectratio]{PoolofBethesda-CarlBloch}
  \caption{\emph{Healing at the Pool of Bethesda} (1883) by Carl Bloch.}
  \label{fig:Bethesda}
\end{figure}

\end{document}