PixPic is an open source photo app from Yalantis allowing you to add stickers to photos, share the photos on social media, and follow people whose photos you like.
PixPic features and excellent interface and is written in Swift and utilizes a number of open source components for toast notifications, pull-to-refresh and more.
Here’s an image from the readme showing PixPic in action:
You can find PixPic on Github here.
See more: Open Source Apps
A great photo app example.