default.latex: Use \ScaleIfNeeded w/ nicer def instead of \maxwidth.

default.latex

@@ -70,13 +70,18 @@ $if(graphics)$
 % Images get their normal width if they fit onto the page, but
 % are scaled down if they would overflow the margins.
 \makeatletter
-\def\maxwidth{\ifdim\Gin@nat@width>\linewidth\linewidth
-\else\Gin@nat@width\fi}
+\def\ScaleIfNeeded{%
+  \ifdim\Gin@nat@width>\linewidth
+    \linewidth
+  \else
+    \Gin@nat@width
+  \fi
+}
 \makeatother
 \let\Oldincludegraphics\includegraphics
 {%
  \catcode`\@=11\relax%
- \gdef\includegraphics{\@ifnextchar[{\Oldincludegraphics}{\Oldincludegraphics[width=\maxwidth]}}%
+ \gdef\includegraphics{\@ifnextchar[{\Oldincludegraphics}{\Oldincludegraphics[width=\ScaleIfNeeded]}}%
 }%
 $endif$
 \ifxetex