How can I rotate an image in PHP?

Here is how you do it. Simple and easy to do. Take this code an play around with it. I am using Bootstrap for the forms.

<?php 
include_once('header.php');
include_once('error.php');
//-90 turns to the right 90 turns to the left and 0 flips it upside down
$rand=rand(1,1000);
//$file1='uploadtest/max-flash.jpg';
$file1='uploadtest/flash.png';
$newfilename='';
if(isset($_POST['rotate'])){
  $rot=$_POST['rotate'];
  if(exif_imagetype($file1) != IMAGETYPE_JPEG){
    	$newfile=rand(1,1000);
  $newfilename='uploadtest/'.$newfile.'.png';
    $source = imagecreatefrompng($file1);
    $rotate = imagerotate($source, $rot, 0);
  //header('Content-Type: image/png');
    imagejpeg($rotate, $newfilename);
    //print_r('Image saved successfully.');
  // Destroy loaded image to free memory
  imagedestroy($source);
   echo 'Not a JPEG image';
}else{
  $newfile=rand(1,1000);
  $newfilename='uploadtest/'.$newfile.'.jpg';
    $source = imagecreatefromjpeg($file1);
    $rotate = imagerotate($source, $rot, 0);
  //header('Content-Type: image/jpg');   
   imagepng($rotate, $newfilename);
    print_r('Image saved successfully.');
  imagedestroy($source);
  echo 'Not a PNG image';

}

if( !rename($newfilename, $file1) ) {  
    echo "File can't be renamed!";  
} else {  
    echo "File has been renamed!";  
} 
echo '<br/><hr/>';
echo '<img src="'.$file1.'?p='.$rand.'" width="400" />';
}else{
echo '<img src="'.$file1.'?p='.$rand.'" width="400" />';
echo '<div class="alert alert-warning">'.$file1.'</div>';
}
?>
<form method="post">
<select name="rotate" onchange="this.form.submit()" class="form-control">
<option>Select</option>
<option value="-90">Turn Right</option>
<option value="90">Turn Left</option>
<option value="180">Flip</option>
</select>
</form>
<?php include_once('footer.php');?>