Right Solution:
Changed
-(void)resizeSprite:(CCSprite*)sprite toWidth:(float)width toHeight:(float)height {
sprite.scaleX = width / sprite.contentSize.width;
sprite.scaleY = height / sprite.contentSize.height;
}
To:
-(void)resizeSprite:(CCSprite*)sprite toWidth:(float)width toHeight:(float)height {
sprite.scaleX = width / [sprite boundingBox].size.width;
sprite.scaleY = height / [sprite boundingBox].size.height;
}
And change background position to:
background.position = CGPointMake(size.width/2, size.height/2);