You really can't measure the rake accurately from a photograph because of parallax distortion (note the camera is not lined up directly from side of the head tube/fork since both fork blades are showing).

Use a 36" straightedge lining it up on the center of the top headset cup and the center of the bottom headset cup. With the front wheel in precise alignment with the fore-and-aft centerline of the frame, measure the distance from the straightedge (at a right angle to the straightedge) to the center of the front axle. That dimension is the fork rake (or offset as it's often called).