Bootstrap 4 在幻灯片中显示默认图像'；没有使用Codeigniter和引导转盘显示图片

我的代码有问题。它不会显示默认图像。这是我的密码

<div id="SS" class="carousel slide" data-ride="carousel">
    <ul class="carousel-indicators">
        <li data-target="#SS" data-slide-to="0" class="active"></li>
        <li data-target="#SS" data-slide-to="1"></li>
        <li data-target="#SS" data-slide-to="2"></li>
    </ul>
    <div class="carousel-inner">
        <?php
        $no=1;
        $default=$this->db->get_where("penyaluran", array("status" => "1"))->result();
        foreach ($default as $pict)
        {                           
        if ($pict->status > "0")
        {
        $g=$pict->foto_dokumentasi;
        $n=$pict->nama_penyaluran;
        }
        else
        {
        $g='image.jpg';
        $n='';
        }

        if ($no == 1)
        {
        $status = 'active';
        }
        else
        {
        $status = "";
        }?>
        <div class="carousel-item <?php echo $status; ?>">
        <img src="<?php echo base_url('uploads/'.$g); ?>" alt="" style="max-height: 300px; width: 1200px; margin-left: auto; margin-right: auto;">
        <div class="carousel-caption">
        <h3><?php echo $n; ?></h3> 
        </div>
        </div>
        <a class="carousel-control-prev" href="#SS" data-slide="prev">
        <span class="carousel-control-prev-icon bg-dark"></span>
        </a>
        <a class="carousel-control-next" href="#SS" data-slide="next">
        <span class="carousel-control-next-icon bg-dark"></span>
        </a>
        <?php
        $no++;
        } ?>
        </div>

它是否显示了非默认图像？不，它只是空白，但当我从我的表格中显示一个或两个图片时，它们会在幻灯片上弹出