从数据库中选择下拉类别后如何从mysql表中显示图像?

I want to show a category based shopping items with images on web page that can be found in the most Online shopping sites.I crated two mysql tables: Ist with id, category_name and 2nd with id, categoryid, product, image_path. I am able to display all product images at a time on page, but I don't know how to show product images of a single category selected from a dropdown list with submit button at the top of the page. I hope my point is clear to all otherwise feel free to ask me.

Below I attached my code that shows all the product images on my php page at a time without any dropdown list. Any ideas and advice on doing this is welcome.

 <head>
 <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1" />
 <title>Untitled Document</title>
 <style type="text/css">
  ul, li {
 list-style-type:none;
 }

ul.display {
width: 500px;
}

ul.display li { 
float: left;  
width: 100px; 
height: 120px;
margin-left: 5px; 
margin-right: 5px;
margin-bottom: 5px;
position: relative;
vertical-align:middle;
text-align:center;
}
ul.display li a img {
 width: 94px; 
height: 114px;
display: inline; 

}

 </style>
 </head>

  <body>

  <div align="center">
 <?php  
  include('connect.php'); 
   $SQL = "SELECT * from becuart";
    $result = mysql_query( $SQL );
    echo "<ul class='display'>";
    while( $row = mysql_fetch_array( $result ) ) {
    $filepath = $row["path"];

    echo "<li>";
    echo "<a href=\"$filepath\"><img src=\"$filepath\" border=\"0\"></a>";
    echo "</li>";
     }
    echo "</ul>";
    ?>
   </div>

   </body>
   </html>`

Because it's way too long -> new answer:

<?php
include 'dbconnect.php';
?>

<form name="product" method="post" action="">
<table align="right" width="10%" border="0" cellspacing="0" cellpadding="0">
<tr>
<td>Category</td>
<td>
<select name="category">

<?php
$sql = "SELECT id, art_name, path FROM category;";
$result = mysql_query($sql);
while ($row = mysql_fetch_assoc($result)) {
?>

<option value="<?= $row['id']; ?>"><?= $row['art_name']; ?></option>


<?php } ?>
</select>
</td>
</tr>
<tr>
<td>&nbsp;</td>
<td><input name="go" type="submit" value="Go" /></td>
</tr>
</table>
   </form>
<div align="center">

 <ul class='display'>
 <?php
 $id = (int)$_POST['category'];
 $sql_search = "SELECT id, art_name, path FROM category WHERE id = $id";
 $search = mysql_query($sql_search);
 if (isset($_POST['go'])) {
 while ($row = mysql_fetch_assoc($search)) {
     ?>


<li><a href="<?= $row['path']; ?>"><img src="<?= $row['path']; ?>" border="0"></a></li>
<?php }

}

else {

}


?>
</div>
SELECT id, name, path FROM table;

...
<select name ...>
<?php
while( $row = mysql_fetch_array( $result ) ) {
?>
<option name="id" value="<?= $row['id']; ?>"><?= $row['name']; ?></option>
<?php
}
?>
</select>

So by javascript/jquery open the img which answers on the POSTed $row['id']; (SELECT path FROM table WHERE id = ?;) or by a simple $_POST['id'] which is the name of the field