我正在尝试将四张图片（猴子、小鸟、小猫和小狗）放入我的 latex 代码中，每张图片都来自不同的网站，但我完全不知道该怎么做。我在这个网站上查过类似的问题，但我仍然感到困惑。
http://wikiclipart.com/monkey-clipart-black-and-white_9254/
https://www.dreamstime.com/royalty-free-stock-image-cartoon-bird-black-white-line-retro-style-vector-available-image37023576
http://weheartit.com/entry/63058954
https://freeclipartimage.com/article/top-84-101-dalmations-clip-art
因为\includegraphics{...}我显然甚至不知道如何正确下载图片，更不用说使用这个命令了。
\documentclass[28pt]{article}
\usepackage{fancyhdr}
\usepackage[includeheadfoot,margin=1.0cm]{geometry}
\usepackage{amsmath,amsthm,amssymb}
\usepackage{enumitem}
\usepackage{mathtools}
\usepackage{framed}
\usepackage{chessfss} %chess figure for HW #2
\usepackage[english]{babel} %table for problem A.43
\usepackage{multirow} %table for problem A.43
%\usepackage[table]{xcolor} color certain blocks in a table
%\usepackage[pass,showframe]{geometry} just to show the margins
\usepackage[makeroom]{cancel}
\usepackage{array} %BETWEEN TWO 2-DIGIT NUMBERS
\usepackage{graphicx}
\newcommand{\N}{\mathbb{N}}
\newcommand{\Z}{\mathbb{Z}}
\newcommand{\thedate}{\today}
\newtheoremstyle{case}{}{}{}{}{}{:}{ }{}
\theoremstyle{case}
\newtheorem{case}{Case}
\newenvironment{theorem}[2][Theorem]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{lemma}[2][Lemma]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{exercise}[2][Exercise]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{problem}[2][Problem]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{question}[2][Question]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\newenvironment{corollary}[2][Corollary]{\begin{trivlist}
\item[\hskip \labelsep {\bfseries #1}\hskip \labelsep {\bfseries #2.}]}{\end{trivlist}}
\begin{document}
\begin{problem}{11}
\textbf{A child matches the pictures}
\write18{http://wikiclipart.com/monkey-clipart-black-and-white_9254/} %wht does this do?
\includegraphics{} %what is this and how can I use this?
\end{problem}
\end{document}