追加した余白除去処理は以下になります。

/*************余白計算*************/
 double imageW = resultImage.size.width;
double imageH = resultImage.size.height;

double diffimageW =(double)((int)resultImage.size.width % (int)appDelegate.resizeImage.size.width);
double diffimageH =(double)((int)resultImage.size.height % (int)appDelegate.resizeImage.size.height);
double simageW = diffimageW/2; //横の余白長さ
double simageH = diffimageH/2; //横の余白長さ
/*************余白除去*************/
cgImage2 = [context createCGImage:result fromRect:CGRectInset(extent, simageW,simageH)];
resultImage = [[UIImage alloc] initWithCGImage:cgImage2];