NEWBIE: Problem with AlbumArt and question about MyPictures

[JueLue]

Hello!
I am quite new to MP and I like very much.
I got two questions I hope to get answered:

1. When playing music, AlbumArt is shown on the screen as it should. My problem: It changes every 3 or 5 seconds. It allways switches between the album art I want and a black (empty) frame of the size of the album art. I tried to change visualization in MediaPlayer, but no effect. What am I doing wrong? (When playing the songs in MediaPlayer with visualization set to AlbumArt everything works fine)

2. Together with the Pictures from my digicam I have stored some little videoclips also take with this digicam (.avi files, each about 30seconds).
Is there any way to show them in the Slideshow together with the pictures? I know this feature from Picasa, where the slideshow shows all pictures in a folder and when it comes to a .avi file just plays it in the same frame as the pictures.

Thank you for your help.
(dont' wonder about my english - I am from Germany)