textwidth in latex code example

Example 1: latex text size

\Huge
\huge
\LARGE
\Large
\large
\normalsize
\small
\footnotesize
\scriptsize
\tiny

Example 2: latex image textwidth

\documentclass{article}
 \usepackage{graphicx}
 \begin{document}
   \includegraphics[width=0.5\textwidth]{file}
 \end{document}