Photoscape is a great free program and you can even make moving avatars. It will crop and you can add text, but you can't really watermark. He might even use Photobucket, you can do all that online.
I have Paint shop Pro 9, and love it. It has a real watermark application, and you can register your picture. It used to be a hundred dollar program, but Jasco sold it to Correl, but still obtain the rights to sell PS pro 9 and you can buy a new copy on ebay for $9.00. It's so worth it!
JASC Paint Shop Pro 9 + Animation Shop 3 **NEW** | eBay.