Cleanup image handling

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UR:

Awesome! 👍
Espresso is an iteresting testing framework for Android to make it easy to write reliable user interface tests. If you want to learn more take a look at this tutorial ( http://www.vogella.com/tutorials/AndroidTestingEspresso/article.html#espresso_introduction ) . Picasso is an easy and powerful library to manage images from the web. A tutorial here ( http://www.androidtutorialpoint.com/networking/android-picasso-tutorial-using-picasso-android-library/ ) . Glide ( http://www.androidhive.info/2016/04/android-glide-image-library-building-image-gallery-app/ ) is another excellent library (I don't understand why you have used both of them). Volley is a modern, fast and efficient REST client. A tutorial and some articles about networking libraries:

Volley tutorial. ( https://www.androidtutorialpoint.com/networking/android-volley-tutorial/ )
Comparison of Android Networking Libraries: OkHTTP, Retrofit, Volley. ( http://stackoverflow.com/questions/16902716/comparison-of-android-networking-libraries-okhttp-retrofit-volley )
A series of articles digging in the Android networking libraries. ( https://android.jlelse.eu/android-networking-i-okhttp-volley-and-gson-72004efff196#.57mo95pf5 )
ConstraintLayout (Google says) allows you to create large and complex layouts with a flat view hierarchy (no nested view groups). If you want to learn more take a look at this tutorial ( https://codelabs.developers.google.com/codelabs/constraint-layout/index.html?index=..%2F..%2Findex#0 ) or at Udacity Course: ConstraintLayout ( https://classroom.udacity.com/nanodegrees/nd801/parts/cb28c357-1bbe-4d13-9f7a-b57d72a0ed6d/modules/f00afa8d-bde2-43d7-9c7e-4d7d52e28a27/lessons/92320789-2acc-42cc-9d64-b1d0e5f1947a/concepts/7cba836c-c3e4-4d2d-8523-d261dd7eadff# ) .