壓縮圖片，是減少的畫素點，從而使相片大小變小，裁剪圖片的改變的照片的尺寸，相片的大小一般變化不大（在這個方法裡面）

//壓縮圖片質量

-(UIImage *)originalImage:(UIImage *)image scal:(float)scal

{

    NSData *imageData = UIImageJPEGRepresentation(image, scal);

    UIImage *newImage = [UIImage imageWithData:imageData];

    return newImage;

}

//壓縮圖片尺寸

-(UIImage*)imageWithImageSimple:(UIImage*)image scaledToSize:(CGSize)newSize

{

    // Create a graphics image context

    UIGraphicsBeginImageContext(newSize);

    // new size

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

    // Get the new image from the context

    UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext();

    // End the context

    UIGraphicsEndImageContext();

    // Return the new image.

    return newImage;

}