On February 12, 2016 Google announced that it is closing Picasa from March 15, 2016. Picasa Web Albums will be closed from May 1, 2016.
Here Google says that:
> The API will still support other functions, including reading photos,
reading albums, reading photos in albums, and uploading new photos.
Although these operations will continue to be supported and the protocol
will remain the same, the content included in the responses and the
operation behavior may change. We'll update the documentation on this
site with specifics on the changes in March.
Picasa Web Albums will be replaced by Google Photos, a photo and video sharing service of Google.
Since we are using Picasa Web Albums in our free product Wallpaper Updater, we announce we will still support Picasa as long as Google will support reading albums and photos from albums.
Next versions of Wallpaper Updater will also support Google Photos and Flickr. If you have any suggestions or questions about Wallpaper Updater functionality, please share them here.