True - it'd work totally fine here.

In general, I've been having a bit of a love/hate relationship with pathinfo lately with regard to how it works for Gallery.  In particular, its splitting of dirname and filename isn't helpful to us and just generates extra code, and its handling of names that start with dot isn't exactly what I thought would be useful for our purposes (e.g. ".album" has empty filename and "album" extension, where ".album" filename with empty extension would be more useful for our purposes).

Been thinking it might be cleanest just to make another helper function somewhere that uses the regex more-or-less identical to that of legal_file::change_extension.  Thoughts?  (BTW, doesn't need to be addressed for this commit...)