Looks good to me, thank you for rescuing that poor guy. He does look very skinny, but I would recommend starting him off small and only feeding every 5 days if he takes them regularly. It would do more harm than good to cram him full of food since his digestive system isn't used to it. Both of my rescues came to me severely underweight and have more than doubled in size, first on a five-day feeding schedule, now on a six-day, and eventually only once a week. You will be amazed at how big of a difference proper care will make in this guy. Both of mine refused to eat in their previous homes because of appalling living conditions, yet they've never refused a meal under my care.
Good luck with him and be sure to maintain proper quarantine procedures