Switching webcam resolutions is flakey.
This is likely not piboxwww's fault. It's likely a problem with telling piboxd to restart mjpeg-streamer and then letting piboxwww know that it's now working. In other words, there is not really any good synchronization on this.
One possible solution might be to start mjpeg-streamer on a new port and return the port ID to piboxwww. Then just kill off the old instance. In fact piboxwww could specify with port to kill, which might allow for multiple camera instances even if only one camera is installed. Maybe.
No data to display