Since the service category does not offer an option to upload an image, you are stuck with needing to have an image available that you can import from a website that is already online.
You could use someone else's image from their website, but unless you get their permission you may get sued!
If you have your own website or know someone willing to let you use their graphic, it is not too hard to do.
I can't get this dialog box to allow me to post the code, but if you email me at my website below, I will email you with the code. Put "please help with code" in the subject so I know you are not spam.