Instagram has been adding new features to its app to help users create better photos. It’s no longer enough for it to be just another photo-sharing social network — we’ve moved past that. But in order for it to scale, Instagram needs to add new tools and features to not only enhance the quality of images shared, but also to maintain the appeal of its service. On Monday, the Facebook-owned company offered up some insights into what it’s doing. In a blog post, software engineer Alex Restrepo shared some thoughts on why Instagram’s straightening tool came into being. As it turns out, finding ways to auto-straighten photos had been something the company had discussed for a while…