Fix issues in an existing Travel mobile app -- 2

Name of the company is TravelBuddha and the product (mobile app) is called Travel UnC ([login to view URL]). iOS and android mobile apps have been uploaded on the appstore but not yet open to public. We need someone to fix few leftover items before we can launch. Looking for YII developer who can work for mobile apps. Also ios and android developers needed. Android app is in Java and iOS is in Obj-C. Language is native. Backend is in php on YII framework. Database is MySql. Android app link - [login to view URL] iOS app link - [login to view URL] The apps would need invite code to signup and test. Pls connect for more details. Issues to be fixed - 1. The app and almost all its features are very slow. Screens with photos are worse in this matter. 2. Quality of photos uploaded by users get distorted and not seen in good quality to rest of the users on the app 3. App crashes once in every 20 times. Android happens more than iOS. 4. Fetched Facebook data not getting properly updated and integrated in various app features.