正常的文件上传方法用于调用另一个函数createThumbnail（）调用

$config['remove_spaces'] = TRUE;
                $config['allowed_types'] = 'jpg|jpeg|gif|png';
                $config['upload_path'] = './images/files';
                $config['remove_spaces'] = TRUE;
                $config['encrypt_name'] = TRUE;
                $this->load->library('upload', $config);
                if ($this->upload->do_upload('img')) {
                    $imgDetailsd = $this->upload->data();
                    $this->createThumbnail($imgDetailsd['file_name'], 200, 200, "./images/site/files", "your thumbnail file location save");
                }

试试这个拇指函数创建你需要的图像尺寸

function createThumbnail($image_name,$new_width,$new_height,$uploadDir,$moveToDir)
{
$path = $uploadDir . '/' . $image_name;

$mime = getimagesize($path);

if($mime['mime']=='image/png') { 
    $src_img = imagecreatefrompng($path);
}
if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
    $src_img = imagecreatefromjpeg($path);
}   

$old_x          =   imageSX($src_img);
$old_y          =   imageSY($src_img);

$width = imagesx( $src_img );
$height = imagesy( $src_img );

if ($width > $height) {
    if($width < $new_width)
        $new_width = $width;
    
    else
    
    $new_width = $new_width;    
    
    
    $divisor = $width / $new_width;
    $new_height = floor( $height / $divisor);
}
else {
    
     if($height < $new_height)
         $new_height = $height;
     else
         $new_height =  $new_height;
     
    $divisor = $height / $new_height;
    $new_width = floor( $width / $divisor );
}

$dst_img        =   ImageCreateTrueColor($new_width,$new_height);

imagecopyresampled($dst_img,$src_img,0,0,0,0,$new_width,$new_height,$old_x,$old_y); 

// New save location
$new_thumb_loc = $moveToDir . $image_name;

if($mime['mime']=='image/png') {
    $result = imagepng($dst_img,$new_thumb_loc,8);
}
if($mime['mime']=='image/jpg' || $mime['mime']=='image/jpeg' || $mime['mime']=='image/pjpeg') {
    $result = imagejpeg($dst_img,$new_thumb_loc,80);
}

imagedestroy($dst_img); 
imagedestroy($src_img);

return $result;

}