Using the desktop software version of Picasa, you have the option to sign in to Picasa Web Albums to upload and share your photos. If you get a "login incorrect" message when you try to sign in to Picasa Web Albums from the desktop version of Picasa, it may be because you have 2-Step Verification turned on in your Google account.
Internet security
Google Account 2-Step Verification & Google Authenticator
Google’s 2-Step Verification is an optional and relatively simple way to provide an extra level of security for your Google account. While it is not a newly introduced feature, it may not be very widely known or used by most. More information on 2-Step Verification for your Google account is given below, including details on how to setup and use it.