Warning: Invalid argument supplied for foreach() in

$results = mysql_query("select * from classpics");

foreach($results as $uno) {
    echo '<td valign="m开发者_如何学编程iddle" align="center"><a class="neutral" href="../images.php?id=' . $uno['id'] . '"><img src="'. $uno['thumbs'].'" border="0" /></a>';
}

The mysql_query returns a resource id, you should fetch an array:

$results = mysql_query("select * from classpics");

while($row = mysql_fetch_array($results)){
  echo '<td valign="middle" align="center"><a class="neutral" href="../images.php?id=' . $row['id'] . '"><img src="'. $row['thumbs'].'" border="0" /></a>';
}

you should fetch data from result

while($data=mysql_fetch_array($results)) {
echo '<td valign="middle" align="center"><a class="neutral" href="../images.php?id=' . $uno['id'] . '"><img src="'. $uno['thumbs'].'" border="0" /></a>';

}

mysql_query returns resource, not an array or any other container. Use mysql_fetch_assoc() to fetch the next result.

while ($uno = mysql_fetch_assoc($result)) {
    echo '<td valign="middle" align="center"><a class="neutral" href="../images.php?id=' . $uno['id'] . '"><img src="'. $uno['thumbs'].'" border="0" /></a>';
}