How to add my own icon images

I found this page on how to customize the AddThis buttons:

https://support.addthis.com/customer/portal/articles/381236-custom-buttons

Do I put this code in the text box inside the plugin?

Also, the code doesn’t specify which icon it’s for. How do I do this for each service I’d like on my site?

This is the code from the page I linked to:

<a class="addthis_button_compact">
         <img src="https://s7.addthis.com/static/btn/sm-plus.gif"
  	 width="16" height="16" border="0" alt="Share" /></a>

So if I upload Twitter, Facebook, Google+, Pinterest and LinkedIn images, I know where to paste the new link. But nothing about this code tells me which service it’s for. So how does it know it’s a Twitter button, etc?

Thank you.

@northstatehillbilly: Custom buttons will only work with native AddThis buttons.

You can also try overriding the style by adding the css to your theme css file(style.css).
.at15t_twitter, .at16nc.at16t_twitter {
background: url(‘./images/your-image.png’);
}

Please provide your site url for more assistance.