Image图片缩小

#pragma mark - 等比例缩小图片
-(UIImage *)narrowImage:(UIImage *)image
{
    CGRect rect = CGRectMake(0, 0, image.size.width/1.8, image.size.height/1.8);
    UIGraphicsBeginImageContext(rect.size);
    [image drawInRect:rect];
    UIImage *narrowImg = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    
    return narrowImg;
}