- (UIImage *)generatePhotoThumbnail:(UIImage *)image {

    // Create a thumbnail version of the image for the event object.

    CGSize size = image.size;

    CGSize croppedSize;

    CGFloat ratioX = 75.0;   

    CGFloat ratioY = 60.0;

    CGFloat offsetX = 0.0;

    CGFloat offsetY = 0.0;

    // check the size of the image, we want to make it

    // a square with sides the size of the smallest dimension

    if (size.width > size.height) {

        offsetX = (size.height - size.width) / 2;

        croppedSize = CGSizeMake(size.height, size.height);

    } else {

        offsetY = (size.width - size.height) / 2;

        croppedSize = CGSizeMake(size.width, size.width);

    }

    // Crop the image before resize

    CGRect clippedRect = CGRectMake(offsetX * -1, offsetY * -1, croppedSize.width, croppedSize.height);

    CGImageRef imageRef = CGImageCreateWithImageInRect([image CGImage], clippedRect);

    // Done cropping

    // Resize the image

    CGRect rect = CGRectMake(0.0, 0.0, ratioX, ratioY); // 设置图片缩微图的区域（（0，0），宽：75  高：60）

    UIGraphicsBeginImageContext(rect.size);

    [[UIImage imageWithCGImage:imageRef] drawInRect:rect];

    UIImage *thumbnail = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    // Done Resizing

    return thumbnail;

}