Apple yesterday mysteriously withdrew its recently-released iPhoto 4.0.2 update.

Macworld sources said they were "looking into" the reason for the disappearing software update, though no information is forthcoming at this time.

When released Apple described the 4.0.2 updates also addresses "minor issues" with Smart Albums, a new feature in iPhoto 4 that enables users to create albums according to set criteria, just like Smart Playlists in iTunes.

However, as the software was released both as a download and through Software Update, it is likely many users will have installed the new, no-longer-available software.

Macworld readers have shared their concerns that if something is wrong with the software that threatens the integrity of their valuable images, they should be told.

An editorial on MacFixIt also questions Apple's opacity in handling such issues. It says: "Users who have already installed the update have a right to know why the software is no longer available, whether or not it's safe to use, and when to expect a "fixed" version."