Check the working snippet, you have to use tild instead of quotes.

Take a look at template literals for more details. Here

var $= jQuery;
    $.dialog({
        columnClass: 'col-md-6 col-md-offset-3 col-xs-6 col-xs-offset-3',
        containerFluid: true,
        title: 'Thank you!',
        content: `<img src="images/icons/success_icon.png"> for confirming the details. You will be notified with latest IPO issuance details`,
    });

<script src='https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js'></script>
<script src='https://cdnjs.cloudflare.com/ajax/libs/jquery-confirm/3.3.2/jquery-confirm.min.js'></script>

i am using alert box with jquery-confirm js. when i using text in content its working fine but when i use image in content Uncaught SyntaxError: Unexpected identifier

<script src='https://ajax.googleapis.com/ajax/libs/jquery/1.12.4/jquery.min.js'></script><script src='https://cdnjs.cloudflare.com/ajax/libs/jquery-confirm/3.3.2/jquery-confirm.min.js'></script><script>
    $.dialog({
        columnClass: 'col-md-6 col-md-offset-3 col-xs-6 col-xs-offset-3',
        containerFluid: true,
        title: 'Thank you!',
        content: '<img src='images/icons/success_icon.png'> for confirming the details. You will be notified with latest IPO issuance details',
    });
    </script>