I have installed TwonkyMedia Server v5.0.40 on my CentOS 5.2 system. I was quite successful with my MP3s being served up, but have had some problems with pictures.
I am using dedicated directories for music, photos and videos. For pictures, the server has found the files and is able to present the directory structure and thumbnails to my Xbox 360. However, when I call for a picture to be displayed, I just get a big X on the screen.
If I use the web-based Media Browser, I do not have this problem.