OC压缩图片

//压缩图片，传入需要的宽高   （拿到图片，调压缩图片的方法，传入需要的宽高）
  [self imageWithImage:image scaledToSize:CGSizeMake(200, 200)];
 
  
//压缩图片
- (UIImage *)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize
{
    UIGraphicsBeginImageContext(newSize);
    [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)];
    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return newImage;
}