根据尺寸压缩图片

#pragma mark - 获取按尺寸压缩过的新图片
+ (UIImage *)getNewImageWithImage:(UIImage *)image size:(CGFloat)tempSize
{
    //获取图片的宽高
    CGSize imageSize = image.size;
    CGFloat imgH = imageSize.height;
    CGFloat imgW = imageSize.width;

    if (imgH == imgW) {//如果是正方形
        imgW = tempSize;
        imgH = tempSize;

    }else if(imgW > tempSize ){//如果宽度大于200/600

        //获取图像宽度的倍数
        CGFloat multiple = imgW / tempSize;
        imgW = tempSize;
        imgH = imgH / multiple;

    }else if(imgH > tempSize ){//如果高度大于200/600

        //获取图像高度的倍数
        CGFloat multiple = imgH / tempSize;
        imgH = tempSize;
        imgW = imgW / multiple;
    }

    //重新赋值图片的宽高
    imageSize.width = imgW;
    imageSize.height = imgH;

    //压缩新图片
    UIGraphicsBeginImageContext(imageSize);
    [image drawInRect:CGRectMake(kZero, kZero, imageSize.width, imageSize.height)];
    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}