Photo sharing service Plixi, which got its start in San Diego as Tweetphoto, has just been shut down by owner Lockerz. The shutdown is not a surprise; Lockerz laid off all of its San Diego office in January. That office had been acquired when Lockerz bought Plixi in January of 2011. Plixi had, as TweetPhoto, developed a service to let users share their photos on Twitter--something which has since been swallowed up into Twitter itself.