Error while retrieving files from server - php

Question

<?php
if(isset($_POST['pic'])){
if ((($_FILES["file"]["type"] == "image/gif")
|| ($_FILES["file"]["type"] == "image/jpg")
|| ($_FILES["file"]["type"] == "image/pjpeg")
|| ($_FILES["file"]["type"] == "image/png"))
&& ($_FILES["file"]["size"] < 300000))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
}
else
{
if (file_exists("upload/" . $_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already exists. ";
}
else
{
move_uploaded_file($_FILES["file"]["tmp_name"],
"upload/" . $_FILES["file"]["name"]);
}
echo "<h1>Done! Looks Great!</h1>";
}
}
else
{
echo "Invalid file";
}
}
?>
<form action="editprofile.php" method="post" enctype="multipart/form-data">
<input type="file" name="file" id="file" />
<p>Image format should be png or jpg.</p>
<center><p class="submit"><input type="submit" name="pic" value="Upload Picture" /></p></center>
</form>
</div>
<p style="text-align:center; font-size:18px;">Current Picture</p>
<?php
$filename = $_FILES['file']['tmp_name'];
?>
<img src="/path/to/the/upload/folder/<?php echo $filename; ?>"/>
<img src="../../upload/foto.PNG" class="picture"/>
I am getting an error like undefined index - file.
Error is in the last few lines.
I basically have a folder which has an image. I want it to display the only image in the folder.

Answer 1

If you open the page for the first time, no form has been sent yet and $_FILES is therefore empty. You try to access $_FILES even in case of first load. This is the faulty line:
$filename = $_FILES['file']['tmp_name'];
You should check that $_POST["pic"] is set before accessing the $_FILES variable (just as you have done on the top of the code).