Image Resize

<form name="frmImageResize" action="" method="post" enctype="multipart/form-data">
    <input type="file" name="myImage" /> 
    <input type="submit" name="submit" value="Submit" />
</form>

<?php
    if(isset($_POST["submit"])) {
        if(is_array($_FILES)) {
            $file = $_FILES['myImage']['tmp_name']; 
            $source_properties = getimagesize($file);
            $image_type = $source_properties[2]; 
            
            if($image_type == IMAGETYPE_JPEG) {   
                $image_resource_id = imagecreatefromjpeg($file);  
                $target_layer = fn_resize($image_resource_id,$source_properties[0],$source_properties[1]);
                imagejpeg($target_layer,$_FILES['myImage']['name'] . "_thump.jpg");
            } elseif($image_type == IMAGETYPE_GIF) {  
                $image_resource_id = imagecreatefromgif($file);
                $target_layer = fn_resize($image_resource_id,$source_properties[0],$source_properties[1]);
                imagegif($target_layer,$_FILES['myImage']['name'] . "_thump.gif");
            } elseif($image_type == IMAGETYPE_PNG) {
                $image_resource_id = imagecreatefrompng($file); 
                $target_layer = fn_resize($image_resource_id,$source_properties[0],$source_properties[1]);
                imagepng($target_layer,$_FILES['myImage']['name'] . "_thump.png");
            }
        }
    }

    function fn_resize($image_resource_id,$width,$height) {
        $target_width = 200;
        $target_height = 200;        
        $target_layer = imagecreatetruecolor($target_width,$target_height);
        
        imagecopyresampled($target_layer,$image_resource_id,0,0,0,0,$target_width,$target_height, $width,$height);
        
        return $target_layer;
    }
?>