This morning I noticed something vaguely different about Google. Just like when a friend or significant other changes something like a haircut, and you get an overall sense that something is different but you can’t pinpoint it.

Finally I saw that a “Photos” tab had joined the standard “Web,” “News” and other top spots after I had logged in to Gmail. This might not be new, but it’s the first time I’ve seen it. After clicking this, I was taken to a sign-up screen for the Web version of Google’s Picasa photo organizer.

Picasa Web Albums was launched in 2006 for Picasa users to upload photos where they can “live” and be shared online. For Google, the product accomplishes a few things.

1. This is one of the many free products from Google that increase its general stickiness and thus traffic (traffic that is monetized in other ways). Google’s reach and registered users position the product better than the competitive iPhoto.

2. It pushes Google further down the path of being a content generator rather than just a raw indexing and search machine. Similar efforts that involve users contributing original content include Google Base and user reviews in Google Maps. Through these efforts, it’s very slowly becoming more like Yahoo!.

3. Speaking of Yahoo!, Picasa Web sharing is a clear shot at Flickr. Flickr is a great product with a commanding market share lead among photo sharing services. But given Yahoo!’s highly public trials and uncertain future, registered users of its various products could be uncertain themselves.

For this reason (and point No. 2), Could Google be pushing Picasa as an opportunity to convert some users with the implicit appeal of a stronger overall brand and an attractive product set (see point No. 1)? If it isn’t, this still brings up an interesting strategy that we could see Google execute in other ways over the coming weeks.