Foursquare, Gowalla, Instagram: Mobile photos are everywhere

It’s been a big week for numbers about photos. Yesterday, location-based service Foursquare launched the latest version of its app with support for photo-sharing, and chief executive Dennis Crowley said later in the day that the service was already approaching one photo uploaded per second. Competitor Gowalla said today that its users have posted 1 million photos. And mobile photo app Instagram also said it has hit 1 million users.