When you using imagecache on the $user->picture, many people have noticed 1 small problem. If someone uploads a new picture, everything appears to work fine, but the user photo stays the same!

What's going on? When a user uploads a picture, it gets renamed to a specific filename - doesn't matter the name of the file you uploaded. Imagecache then makes a copy of that file to display. (Technically this doesn't happen until the first time the image is viewed with a particular preset). When the new user image is uploaded, it gets the very same name as the previous one, again regardless of the actual filename that was uploaded. Now imagecache will think it already has a cached version of that image, because it just checks the filename and sees that it exists!

So I was all about to post on how to fix that, basically by linking to Nate Haug's excellent post on how to do just that - but the Imagecache module maintainers have just made a new release (for Drupal 5) that includes a fix for the issue! So the new solution is - download the latest version of the Imagecache module!