I know the URL looks like it's a static JPG, but the image does change every 30 mins - just hit refresh. I got it from this Bulgarian weather site: http://weather.digsys.bg/c/index.pl%3Fplace=48&action=real&lang=_eng.html this also has an MPG of the last 24 hours, which is interesting.
I haven't been able to find a live streaming feed from it, and curiously the Samokov Hotel website makes no mention of it: http://www.samokov.com