第一步先用composer安装一下图片处理的扩展,在fastadmin的根目录里面直接敲命令

composer require topthink/think-image

 第二步直接找到公共上传类，application/common/library/Upload.php，在最下面新添加一个方法

public function thumb_image(&$params,$ratio = 10)
    {
 
        //图片大于300K才进行压缩，先判断是横图，还是坚图，设置图片宽最大810，高最大540，做出相对应的比例压缩
        if($params['filesize']>300000){
            //横图＝宽比高大
            if($params['imagewidth']>=$params['imageheight']){
                if($params['imagewidth']>=810){
                    $width = 810;
                    $height = round($params['imageheight']/($params['imagewidth']/810));
                }else{
                    $width = $params['imagewidth'];
                    $height = $params['imageheight'];
                }
            }else{//坚图＝高比宽大
                if($params['imageheight']>=540){
                    $height = 540;
                    $width = round($params['imagewidth']/($params['imageheight']/540));
                }else{
                    $width = $params['imagewidth'];
                    $height = $params['imageheight'];
                }
            }
 
            $pathname = $params['url'];
            $file = $this->file;
            $image = \think\Image::open($file);
            $image->thumb($width, $height)->save('.' . $pathname);
            $image_root_path = ROOT_PATH . '/public' . $pathname;
            $params['imagewidth'] = $width;
            $params['imageheight'] = $height;
            $params['filesize'] = filesize($image_root_path);
        }
    }

第三步找到里面的 upload() 方法，在文件上传完成，将要添加到attachment表的图片数据时进行等比压缩处理

 代码如下：

if (in_array($this->fileInfo['type'], ['image/gif', 'image/jpg', 'image/jpeg', 'image/bmp', 'image/png', 'image/webp']) || in_array($this->fileInfo['suffix'], ['gif', 'jpg', 'jpeg', 'bmp', 'png', 'webp'])) {
            $this->thumb_image($params);
        }