new table rows with a for loop

[phpscripters]

Hey,

I am making a photo gallery program, I want this thing to have a table with 4 images across, then go down and make a new row, and have 4 more images, etc. I have written some code that made sense to me, but my program doesn't go down, it just keeps adding on to the row thats there. Any ideas?

 for($i = 0; $i < $num; $i++) {
 $picinfo = mysql_fetch_assoc($doget);
 $name = $picinfo["name"];
 $url = $picinfo["url"];

 if($counter == 3) {
  echo "</tr>";
  echo "<tr>";
  echo "<td width=\"25%\">";
  echo "<br><center><a href=\"$url\"><img src=\"$url\" height=\"$thumbnailpic_height\" width=\"$thumbnailpic_width\"></a></center><br>";
  echo "<center>$name</center>";
  echo "</td>";
  $counter = 0;
 } else {
  echo "<td width=\"25%\">";
  echo "<br><center><a href=\"$url\"><img src=\"$url\" height=\"$thumbnailpic_height\" width=\"$thumbnailpic_width\"></a></center><br>";
  echo "<center>$name</center>";
  echo "</td>";
  $counter = $counter++;
 }

 }

[phpscripters]

i forgot to add this... before the for loop i have

echo "<tr>";
$counter = 0;