Images no longer show up!

I am running 6.14, along with FCKeditor and IMCE.

I have a forum and set the default user photo (avatar/icon) in this directory: example.com/images/default_photo.jpg
This photo is working fine.

I also set up FCKeditor and IMCE to allow users to upload photos (custom avatar and photos to embed in forum posts)
The directory for each user is: example.com/sites/default/files/users/user#
The directory for each user's avatar is: example.com/sites/default/files/pictures
(and Drupal renamed the avatar to "picture-user#.jpg)

For some reason, the custom avatars and embedded photos are no longer showing up! I thought it might be an image viewing problem, but the default avatar (which is kept in a separate directory) shows up fine. The only issue I'm having is with the individual users' files.

Any help is appreciated!