anchor.diff:  (defun set-layer-color (session layer-index new-color)
     (setf (elt (session-layer-colors session) layer-index) new-color))
   
  -(defun generate-image (session)
  +(defun generate-image ()
     ;; run-program
     )
   
  
positive.code:   (start-session))
  
  (define-easy-handler (generate-image :uri "/picture/generate") ()
    "Handler for loading and writing the picture/layers being used by the given session."
    (start-session)
    (setf (content-type*) "image/png")
  )
  
  (define-easy-handler (thumbnail :uri "/thumbnail") (picture-id)
  
negative.code: set the colours of the layers, and see the resulting image.")
    (:use :common-lisp
  	:imago
  	:json
  	:hunchentoot)
    (:export :start-server))
  (in-package :design-center)
  