How do you find an image center without arcade physics ?
As an example I am using a matrix as exported by inkscape , but elements order looks different.
-45 degrees rotation about (0,0) of a
10 by 10 px image square
es ( can't figure out if correct) :
var tank = this.add.image(-5, 5, 'testImg');
var ar = [0.70710678,0.70710678,0,-0.70710678,0.70710678,0];//svg inkscape matrix
var mat = new Phaser.Matrix();
console.log(tank.getBounds(mat.fromArray(ar)));