PIXI getting image width,height - pixi.js

Question

I need to get size of image that I just added to stage and set it to defaultX and defaultY before I call the autorenderer, but I can't seem to grab the size.
How do I grab the size?
Also, from what I got so far, I think the best way to set the size is including with autorenderer. But what would be the implication here if I resize() later?
Any help will be appreciated. Thank you.
my code:
this.stage = new PIXI.Container();
var texture = PIXI.Texture.fromImage('background.png'); //1610x640
var spr = new PIXI.Sprite(texture);
this.stage.addChild(spr);
defaultX = texture.width;
defaultY = texture.height;
this.renderer = PIXI.autoDetectRenderer(defaultX, defaultY); //640x690
this.renderer.resize(x,y); // I know this works with other values
// eg if I hardcode with 1610,640
// but texture.width doesn't work and
// I don't want to hardcode it

Answer 1

Your image can not be loaded when you call texture.width.
I use next construction:
this.stage = new PIXI.Container();
this.renderer = PIXI.autoDetectRenderer(640, 690); //640x690
var baseTexture = new PIXI.BaseTexture('background.png');
// can be loaded from cache
if (baseTexture .hasLoaded) {
createSprite(baseTexture);
} else {
baseTexture .on('loaded', function() {
createSprite(baseTexture); // or this
});
}
function createSprite(baseTexture) {
var texture = new PIXI.Texture(baseTexture);
var spr = new PIXI.Sprite(texture);
this.stage.addChild(spr);
defaultX = texture.width;
defaultY = texture.height;
this.renderer.resize(defaultX,defaultY);
}