Earlier this month, location-based service Gowalla went on the offensive against rival Foursquare — by linking up with them . Yes, they created a way for you to use Gowalla to check-in on Foursquare (and Facebook). Why would they do that? Because they said that users told them they felt the Gowalla experience was better, but many of their friends were already using Foursquare. So what did that Gowalla experience include that Foursquare didn't? Well, comments and pictures, for starters. Well, you can strike both of those off the list today. Yes, Foursquare is finally adding both highly requested features to the service. At first, they'll be available on the iPhone app and the website, but the plan is to quickly get them to Android (next week, we're told) and BlackBerry (next month). And the service has three other high-profile startups on board at launch to help with the picture element: Instagram , PicPlz , and Foodspotting .