How do I use the Image Checkboxes Widget?

I really want to use this widget but it asks for image URLs in order to make the images show up. How do I do this when the pics are just from my computer. They don't have URLs, do they??

Thanks!!

You have to upload them to your server, or any of your cloud storage providers like Dropbox and Google Drive: http://www.syncwithtech.org/2014/09/direct-download-link.html 

Let us know if you need more help.