1. 修改 image.helper.php 文件
    • 找到以下代码： 
      $srcW = ImageSX($im);
$srcH = ImageSY($im);
if($srcW <= $toW && $srcH <= $toH) return TRUE;
$toWH = $toW / $toH;
$srcWH = $srcW / $srcH;
if($toWH <= $srcWH) {
    $ftoW = $toW;
    $ftoH = $ftoW * ($srcH / $srcW);
} else {
    $ftoH = $toH;
    $ftoW = $ftoH * ($srcW / $srcH);
}
    • 修改为： 
      $srcW = ImageSX($im);
$srcH = ImageSY($im);
if($srcW <= $toW && $srcH <= $toH) return TRUE;
$toWH = $toW / $toH;
$srcWH = $srcW / $srcH;
$ftoH = $toH;
$ftoW = $toW;
if ($toWH <= $srcWH) {
    $src_Y = 0;
    $src_X = ($srcW - $srcH * $toWH) / 2;
    $srcW = $srcH * $toWH;
} else {
    $src_X = 0;
    $src_Y = ($srcH - $srcW / $toWH) / 2;
    $srcH = $srcW / $toWH;
}