Edit in JSFiddle

<div id="one"><a href="/internal">Internal</a></div>
<div id="two"><a href="/another-link" target="_blank">Internal to open in another tab</a></div>
<div id="three"><a href="http://www.google.com">Google</a></div>
<div id="four"><a href="https://www.paypal.com">Paypal</a></div>
<div id="five"><a href="http://www.amazon.com">Amazon</a></div>
a[href*="//"]:not([href*="jsfiddle.net"]):after,
a[target="_blank"]:after {
  margin-left: 3px;
  content: url(data:image/svg+xml,%3C%3Fxml%20version%3D%221.0%22%20encoding%3D%22UTF-8%22%20standalone%3D%22no%22%3F%3E%3Csvg%20xmlns%3D%22http%3A%2F%2Fwww.w3.org%2F2000%2Fsvg%22%20width%3D%2212%22%20height%3D%2212%22%3E%3Cpath%20fill%3D%22%23fff%22%20stroke%3D%22%2306c%22%20d%3D%22M1.5%204.518h5.982V10.5H1.5z%22%2F%3E%3Cpath%20d%3D%22M5.765%201H11v5.39L9.427%207.937l-1.31-1.31L5.393%209.35l-2.69-2.688%202.81-2.808L4.2%202.544z%22%20fill%3D%22%2306f%22%2F%3E%3Cpath%20d%3D%22M9.995%202.004l.022%204.885L8.2%205.07%205.32%207.95%204.09%206.723l2.882-2.88-1.85-1.852z%22%20fill%3D%22%23fff%22%2F%3E%3C%2Fsvg%3E)
}

div {
  margin: 20px;
}