Pinterest, every girlfriends favorite network, is positioned to leap frog Instagram with a well-played mobile photo-sharing app.<p>Although they currently allow you to take a photo with your camera in their current app; it's not a core focus and lacks photo editing features.<p>If the app shares to Twitter and Facebook as well; I could see a significant number of people switching over from Instagram and focus on building their identity on Pinterest. Mobile photo-sharing is a wedge that could lead them to interest-targeted mobile status updates.<p>Finally, it's an opportunity to de-focus brands from Instagram back to contributing to Pinterest. Brands have already found the highest ROI on Pinterest so it would make sense for them double-down and have real-time photo content on their a "what's happening now" board.<p>Could a stand-alone camera app be Pinterest's new killer product?