JSFiddle - React, Tailwind, and code Playground

HTML

<div class="textarea" contenteditable="true"></div>

CSS

.textarea {
    height: 700px;
    border: 1px solid #ccc;
}

.temp_added_image {
    max-width: 100%;
}

JavaScript

$(function(){
    var div = $(".textarea");
    div.append('Some text before an image <br><img class="temp_added_image" src="http://www.deshow.net/d/file/car/2010-10/seat-electric-car-879-2.jpg"><br><br>');
    div.html = div.html;
    div.focus();
});