Note: This tutorial was targeted for a previous version of the Phaser library. The updated version can be found here.
Phaser is a robust, famous multi-platform game development framework based on the fast PIXI library. It is getting much attention now-a-days. There are so much examples there in http://examples.phaser.io/, and thus learning Phaser is very simple.
First of all, thanks for the team behind this excellent library. When we consider multi-platform development, we need to think about multiple resolutions and devices. Using high quality assets in big screen devices will ensure your game will look beautifully on those. But this high quality assets will affect performance of low end devices, so we need to load the graphics for each devices separately and scale up or down the game according to the screen resolution.