Google has changed its toolbar navigation to direct users to Google+ Photos instead of Picasa. This may indicate that Google is phasing out Picasa in favor of a socially integrated image and gallery service.
Is Plus Replacing Picasa?
A recent tweak to Google's top toolbar (a.k.a., the Google+ Bar) may indicate that Picasa is on the path toward product sunset. Google Operating System was the first to take note of the change in Google's toolbar navigation. While the "photos" section previously directed users to Picasa, it now directs any user who's logged into a Plus account to the Google+ Photos page.
At the very least, Picasa is seeing some decreased priority when set side-by-side with Plus. While this on its own isn't enough to leap to that conclusion that Picasa is being bled out into Google's social network, previous rumors of a name change and the numerous Google product cuts in the Larry Page era all add to the weight of this speculation.
It's not likely that Google will sunset Picasa until Plus has integrated the core features, but that process is already underway. As the notification on Picasa's home page indicates, having a Plus account means albums have already become tag-based, shareable, and trigger notifications on Google+. Additionally, several of the mobile features of Plus, including automatic uploads, are integrated with Picasa by default.
As the features of Picasa are added to Google+ Photos and all Google account users (including those based in Apps) gain access to Plus, Google may move users over to Plus as their image location. This raises additional questions on what other services may be folded into Plus in the future. Could Blogger become Google+ Blogs? Could Buzz become Google+ Updates while Orkut becomes Google+ Networking? Or, in an extreme show of commitment to their social front, could YouTube become Google+ Videos?
For the time being, we don't know anything for sure except that the link has changed. Those who want to use Picasa can still go to the original link (picasa.google.com). Additionally, for those who don't have a Plus account or aren't logged in, the top toolbar still links to Picasa.