The best thing Google could do today to snag some market share in the photo sharing space would be to get SnapSeed updated to share directly to Twitter (and play nicely while doing it). Leave the photos of kids and puppies to Istagram/Facebook and get the really good photographers who haven’t moved to Google+ yet get their feet wet with the easy Twitter integration. They’ll inevitably share to G+ while they’re at it.
I can’t help but think Instgram has really screwed up by starting this fight with Twitter.
Facebook and G+ are such different things, and one area where G+ destroys Facebook is in photography. Production and consumption there is so far beyond what is possible on Facebook.