www.wysiwygwebbuilder.com

As I can see you have 2 ways that you can "implement" your own icons. In both options you must first make the icon vectorized if it's not already in that state. Then you must make a font of the icon, when doing this you can fill up with a whole library of icons in the font. There's a free fontediting software on the market called "Font Forge": https://fontforge.github.io/en-US/downloads/

1: Easiest method, just generate a truetype font (.ttf) which you copy in to the "C:\Documents\WYSIWYG Web Builder\system\clipart" folder... Now you can use the icon library you made with the Clipart tool.
2: The little harder way is to add the font to the "Icon Font" See Pablos tutorial, scroll down: http://www.wysiwygwebbuilder.com/iconfonts.html

But with this method you get more options for the behaviour of the icons.

This is one "Clipart" ttf font that you install in "C:\Users\user\Documents\WYSIWYG Web Builder\system\clipart:
http://www.chevere.ec/web_storage/GlobeIcons.zip

It's a open source license (Free) that I have modified with several more cliparts. Globes are always useful