monline

If you put pictures in a watched folder inside Picasa, then the folder will appear in the app's folder list the next time you start it. It'll show you the picture count behind the folder's name as it should. However what if you've other (sub-)folders in there too? Picasa shows only the top-level contents of a folder (when you select it in the folder list), ie. you don't see in a selected folder the pictures of it's sub-folders (these sub-folders appear in Picasa's folder list as separate items). However, the folder deletion process works recursively, ie. it'll delete all sub-folders (and all their content) too!

From the UI this is not trivial. A user might reasonably expect that if you delete a folder with 3 pictures inside it, then only those 3 pictures will be deleted. In Picasa you don't see the folder hierarchy, thus you can easily forget whether there're any sub-folders inside the folder that you're about to delete or not.

Here's what happened to a user I know ...
All photos were stored in the directory E:\photos in a well organized structure (sub-folders based on year and inside further sub-folders based on the topic/events). She copied some pictures directly into E:\photos, worked with them and afterwards wanted to get rid of them. In the folder list these pictures appeared as a new folder named "photos". She was not suspicious (I cannot blame her for this) and selected this "photos" folder in Picasa (displayed as having only 3 pictures in it) to be deleted. Picasa was very quick. Deleted a few thousand photos (the entire photo collection) in a (few) second(s).
Fortunately I was able to recover all photos using the Ultimate Boot CD for Windows (and more specifically the free edition of Handy Recovery), but it was quite a shock to the user.

Searching for the picasa delete folder keywords took me to the appropriate help page, which contains the warning that Picasa should tell you itself:


PS: Picasa pops up a confirmation dialog, but asks only if you really want to delete the folder ... no warning about existing (and not empty) sub-folders and their contents (at least not in the Hungarian translation). Imho it shouldn't allow recursive deletions at all. If you select a folder to be deleted, it should not affect other folders in Picasa's folder list. And for this to happen, the app should prevent recursive folder deletion. It's way too easy to forget about, even for experienced users.