//Based on documentation I know that I have to create an instance from
UIGraphicsImageRendererFormat and set its scale to my desired scale but how can I use it???

UIGraphicsImageRendererFormat * format = [UIGraphicsImageRendererFormat defaultFormat];
format.scale=1.0;
UIGraphicsImageRenderer*renderer = [[UIGraphicsImageRenderer alloc]initWithBounds:self.bgImageView.layer.bounds];

UIImage*image= [renderer imageWithActions:^(UIGraphicsImageRendererContext*_Nonnull myContext){
        [self.bgImageView.layer renderInContext: myContext.CGContext];
}];