in lion the folder 'Photo Booth Library' has some extended file attributes that will make you open photo booth rather than simply the folder. to access your files in the finder, eg. for using them in avatars or email attachments you need the terminal (Finder -> Applications -> Utilities -> Terminal) and have to go in the terminal to your Pictures folder by typing
cd Pictures/
now, you can either
- remove those extended file attributes (you'll need the developer tools for this) by typing
xattr -d com.apple.FinderInfo Photo\ Booth\ Library/
this removes the nice icon of the folder (side-effect, sorry) and changes the behavior of finder so that it just opens that folder rather than opening the photo booth app.
- or make a symbolic link to the place where your pictures are stored in the library. In your Pictures folder do
ln -s Photo\ Booth\ Library/Pictures PhotoBoothPics
the link PhotoBoothPics will be accessible in your finder as you would expect from a standard directory.
For beginners, I recommend the second version. But maybe some expert can figure out which bit to unset in the finder info (rather than deleting the whole object).