iOS 改变图片的大小

+ (UIImage *)originImage:(UIImage *)image scaleToSize:(CGSize)size {

    UIGraphicsBeginImageContextWithOptions(size, NO, [UIScreen mainScreen].scale);//    size是想要设置成的大小

    [image drawInRect:CGRectMake(0, 0, size.width, size.height)];

    UIImage *scaleImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();    return scaleImage;}

创建一个帮助类，添加上面的类方法即可获取满足大小要求的图片。