I haven't used this myself so can only go by what Google say on their pages. It
appears that they have slightly altered the windows version of Picasa and have
also added some "improvements" to wine to enable the two to run as a package.
Presumably, the windows version wouldn't run "as is" through wine? I don't know
if you have followed through the pages but all I know has been gleaned from the
following two links: http://picasa.google.com/linux/learn_more.html

http://picasa.google.com/linux/faq.html#23

Sorry I can't give you any further information. Let us know how you get on with
it.