I have noticed that photos and videos will not open in WP PrettyPhoto if there are certain characters in the address. For instance, I inserted a gallery and one photo was named blue+house.jpg. All the photos opened correctly except for blue+house.jpg. It opened fine when I removed the plus sign.
That I can take care of myself, the other problem I can't though. If a YouTube address contains an underscore in the video ID it will not work either.
Any way around this?