crm/app/model/ExamQuestion.php

<?php

namespace app\model;

use think\Model;

class ExamQuestion extends Model
{
    //
    public function getImgsAttr($value)
    {
        if (empty($value)) return $value;
        $imgs = explode(',',$value);

        $ali_oss_bindurl = config('app.ali_oss_bindurl');
        foreach ($imgs as $k => $v) {
        	$imgs[$k] = 'https://' . $ali_oss_bindurl . '/' . $v;
        }
        return $imgs;
    }
}