MYSQL插入提交按钮PHP

我正在生成一个图像列表，并希望根据是否在我的图像旁边按下了提交按钮来插入特定的图像。

这是我生成图像列表的代码。图像旁边是提交按钮，如计数和其他数据：

// Display results
foreach ($media->data as $data) {
echo "<a href='"{$data->link}'"</a>";
echo "<h4>Photo by: {$data->user->username}</h6>";
echo $pictureImage = "<img src='"{$data->images->thumbnail->url}'">";
echo "<h5>Like Count for Photo: {$data->likes->count}</h5>";
echo "<form>";
echo '<input type="submit" onClick=post()>';
echo "</form>";
}

然后我试图将这张照片插入我的数据库：

InstagramImages（DB）-图像（字段）

function post() {
        $hostname = "redacted";
        $username = "redacted";
        $dbname = "redacted";
        //These variable values need to be changed by you before deploying
        $password = "redacted";
        $usertable = "InstagramImages";
        //Connecting to your database
        mysql_connect($hostname, $username, $password) OR DIE ("Unable to 
        connect to database! Please try again later.");
        mysql_select_db($dbname);
        $sql="INSERT INTO $usertable (image) VALUES ('$pictureImage')";
        if (!mysqli_query($con,$sql)) {
            die('Error: ' . mysqli_error($con));
        }
        echo "1 record added";
        mysqli_close($con);
}

如有任何帮助，我们将不胜感激。我需要帮助为php变量$pictureImage创建正确的INSERT查询。