How to post a photo to Facebook using the Facebook Graph API?

Question

Facebook

I would like to get a step-by-step instruction for publishing a photo on Facebook using the Facebook Graph API. When I make a post request " https://graph.facebook.com/me/photos?",{"source ": " source.unsplash.com/featured/?quote ", "access_token":token} I get response {'error': {'message': '(#324) Requires upload file', 'type': 'OAuthException', 'code': 324, which requires the file to upload, which is specified in my source.
I'm probably missing some steps, like getting the URL of the download server, post request to this server, how it works with the VK API.