\documentclass[a4paper]{article}
\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
\usepackage{amsmath}
\usepackage{ amssymb }
\usepackage{graphicx}
\usepackage[colorinlistoftodos]{todonotes}
\usepackage{geometry}
\usepackage{textcomp}
\usepackage{float}
\usepackage{tikz}
\usepackage{caption}
\usepackage{stmaryrd}
\title{Título}
\author{Autor}
\date{\today}
\begin{document}
\maketitle
\section{Introducción}
\begin{figure}[!h]
\centering
\begin{tikzpicture}
\node[inner sep=0pt] (frog) at (10,50)
{\includegraphics[width=0.55\textwidth]{frog.jpg}};
\end{tikzpicture}
\caption{Animal anfibio}
\end{figure}
\end{document}
