Do I need to upload the image to an external site?
I'm afraid (currently) yes.
Do you plan to make the process easier? One would think, with Bitrix promoting itself as a marketing tool, that you would have this issue solved by now. To be honest, being able to add images to templates is a pretty basic feature. This feature is utterly necessary.
Edited: Gerencia Vela Esthetics - 08/31/2017 02:18:31(Didn't make my question)