Front Row/iPhoto

When using the main screen in iPhoto in Front Row and browsing through the many photo albums I have, some folders have an image by the side of the folder name, but some dont.

Is there a reason why this happens? I can't work it out

I just had a look at my own photo's through Front Row and my albums all showed the contents as a little slideshow to the left of the album name.

To create my albums I highlighted a group of photos and went to the menu and selected "New Album From Selection". If I needed to add a photo I would drag'n'drop it. That's all I can think of.