1.Alarmofire: For networking added using Cocoapods
2.LiquidCollectionViewLayout.swift: imported from : https://github.com/instamobile/swift-tutorials/blob/master/LiquidCollectionViewLayout.swift
but I made my own version of it and added directly to the project.

I used https://pixabay.com free API
you will find a key added in the code, please if any trouble just send me to replace the key or simply sign up to create a new one in this page :
https://pixabay.com/api/docs/

I added to classes for unit testing :
NetworkManagerTests
TestPixabayRequest