+(UIImage *)comPRessImageWith:(UIImage *)image width:(float)width height:(float)height{    float imageWidth = image.size.width;    float imageHeight = image.size.height;        float widthScale = imageWidth /width;    float heightScale = imageHeight /height;        // 創建一個bitmap的context    // 并把它設置成為當前正在使用的context    UIGraphicsBeginImageContext(CGSizeMake(width, height));        if (widthScale > heightScale) {        [image drawInRect:CGRectMake(0, 0, imageWidth /heightScale , height)];        }    else {        [image drawInRect:CGRectMake(0, 0, width , imageHeight /widthScale)];    }        // 從當前context中創建一個改變大小后的圖片    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    [newImage retain];    // 使當前的context出堆棧    UIGraphicsEndImageContext();        return newImage;    }