LOPOZ  If you don't want that Google Update crap, do this:

1. Mount the DMG you downloaded

2. Right-click on the .mpkg and 'Show Package Contents'

3. Navigate to 'Contents/Resources'

4. Install 'Picasa Web Albums Uploader' for the stand-alone app or 'PicasaWebAlbumsUploaders' for the iPhoto plugin.

At the end of the installation an error message will appear, but it will work fine AND without the Google Update mess :)  
(Version 1.3.0.536)

LOPOZ  The app looks great and it's free, but it cleans files not associated with the app I'm trying to remove (as a test).

I tried zapping Extendmac Flow as a test using AppZapper and AppCleaner.

Result:

AppZapper found three files: the app itself :P, App Support folder and a plist.

AppCleaner found 6 files: the app itself, a plist and FOUR unrelated plist files which contained the word 'flow' in them.

Needless to say removing those plists would have caused me to lose the settings for the apps associated with the plists.

Not recommended. It seems AppZapper, even though 2 years old, is still on top of it's game..  
(Version 1.2.2)