I want to click pictures with picamera and send them to my pythonanywhere...that should run a specific python script and return the output again to my rpi.
How is that possible?.. 
I have a hacker account on pythonanywhere.
You can do that by creating a web app on PythonAnywhere and then have picamera upload the picture. The endpoint on PythonAnywhere could then do the processing that you want and return it's results as the response to the request.
How to connect to pythonanywhere script from my rpi