该程序可以实现:
1.同时上传5张图片
2.同时生成两种尺寸的缩略图
3.保存到mysql

controllers：upload.php文件：

复制代码 代码如下:<?php
class Upload extends Controller {
  function go() {
    if(isset($_POST['go'])) {
      //初始化
      $config['upload_path'] = 'album/source';
      $config['allowed_types'] = 'gif|jpg|png|bmp|jpeg';
      $config['encrypt_name'] = TRUE;
      $config['remove_spaces'] = TRUE;
      $config['max_size']  = '0';
      $config['max_width']  = '0';
      $config['max_height']  = '0';

      $this->load->library('upload', $config);

      //170*170图片
      $configThumb = array();
      $configThumb['image_library'] = 'gd2';
      $configThumb['source_image'] = '';
      $configThumb['create_thumb'] = TRUE;
      $configThumb['maintain_ratio'] = TRUE; //保持图片比例
      $configThumb['new_image'] = 'album/thumb';
      $configThumb['width'] = 170;
      $configThumb['height'] = 170;
      //600*600图片
      $configLarge = array();
      $configLarge['image_library'] = 'gd2';
      $configLarge['source_image'] = '';
      $configLarge['create_thumb'] = TRUE;
      $configLarge['maintain_ratio'] = TRUE; //保持图片比例
      $configLarge['new_image'] = 'album/large';
      $configLarge['width'] = 600;
      $configLarge['height'] = 600;

      $this->load->library('image_lib');

      for($i = 1; $i < 6; $i++) {
        $upload = $this->upload->do_upload('image'.$i);      
        if($upload === FALSE) continue;
        $data = $this->upload->data();//返回上传文件的所有相关信息的数组
        $uid = $this->session->userdata('uid');
        $uploadedFiles[$i] = $data;

        if($data['is_image'] == 1) {
          //初始化170*170 
          $configThumb['source_image'] = $data['full_path']; //文件路径带文件名
          $this->image_lib->initialize($configThumb);
          $this->image_lib->resize();
          //初始化600*600
          $configLarge['source_image'] = $data['full_path']; //文件路径带文件名
          $this->image_lib->initialize($configLarge);
          $this->image_lib->resize();
        }

        //插入图片信息到album表,插入的文件名为source目录文件名
        $picture = array(
            'filename' => $data['file_name'],
            'albumID' => $this->uri->segment(4,0),
            'uid' => $this->session->userdata('uid'),
            'dateline' => time(),
            'describe' => '',
            'click' => 0
        );

        $this->load->model('album_model');
        $this->album_model->AddPic($picture);
        $picture = array();
      }
    }

    /* 转出 */
    $albumID = $this->uri->segment(4);
    $backurl = site_url() . 'photo/editpic/album/' .$albumID;
    $this->session->set_flashdata('msg','图片上传成功.');
    redirect($backurl,'refresh');
  }
}

views:new_pic.view文件：

复制代码 代码如下:<form method="post" action="<?php echo site_url() ?>photo/upload/go/<?php echo $albumID ?>" enctype="multipart/form-data">
  <input type="file" name="image1" class="files"/><br />
  <input type="file" name="image2" class="files"/><br />
  <input type="file" name="image3" class="files"/><br />
  <input type="file" name="image4" class="files"/><br />
  <input type="file" name="image5" class="files"/><br />
  <br />
  <p><input type="submit" name="go" value="上传照片" class="button" /></p>
</form>

此外需要注意：

1.要一次上传几个文件，修改表单和控制器中循环部分的参数就好。
2.album\\source 是上传后原图目录  large和thumb分别是两次执行$this->image_lib->resize();后存放缩略图的目录
3.缩略图文件名如需和album\\source目录一致，请添加参数 $config['thumb_marker'] = '';
4.$picture这部分数组是保存到数据库的东西，可以不用管了。