Tumblr has updated its iOS app today to roll in its recently-introduced Photoset feature into its primary app. Photosets were first released in a standalone app last fall, which allowed users to compile a collection of photographs, design a quick layout, and share the set with family and friends. The feature didn't require a Tumblr account, but now the microblogging service's iPhone app has Photosets built-in so you can easily post one of the collections to your blog. In addition to the new feature, Tumblr has borrowed some Instagram functionality, now allowing users to double-tap photos in the app to heart them. Lastly, the app now includes a redesigned camera user interface.