Cannot Update Image In PHP&MYSQL - php

Question

hi guys i am working on a project where i have a student_edit.php file which updates the students
details all my data is updated successfully but there is one problem when i update lets say only two fields and not all then image is blanked and my fields updated successfully.
what i am doing is that i am showing student picture and besides it i have another input fields to browse image to update image. What i want is simple that if i am not updating image instead i update other fields image should be still there and not become blank.
Necessary code snippets is like that:
<?php
$file_name = $_FILES['picture']['name'];
$tmp_name = $_FILES['picture']['tmp_name'];
if (copy($tmp_name, "images/" . $file_name)) {
$picture = "images/" . $file_name;
}
if (!isset($_POST['picture'])) {
$res = mysql_query("UPDATE student SET `id`='$id',`branch_id`='$branch_id',`class_id`='$class_id',`section_id`='$section_id',`roll_number`='$roll_number',`student_name`='$student_name',`father_name`='$father_name',`dob`='$dob',`student_address`='$student_address',`gender`='$gender',`status`='$status',updated=now() WHERE id='$id'") or die(mysql_error());
}
else {
$res = mysql_query("UPDATE student SET `id`='$id',`branch_id`='$branch_id',`class_id`='$class_id',`section_id`='$section_id',`roll_number`='$roll_number',`student_name`='$student_name',`father_name`='$father_name',`dob`='$dob',`student_address`='$student_address',`gender`='$gender',`status`='$status',`picture`='$picture',updated=now() WHERE id='$id'") or die(mysql_error());
}
?>
and their is picture area where i call pics
<p>
<label for="picture"><strong>Picture:</strong> </label>
<img src="<?php echo $rec['picture'];?>" width="100" height="100"/>
<input name="picture" type="file" value="">
</p>
and their is picture area where i call pics
<p>
<label for="picture"><strong>Picture:</strong> </label>
<img src="<?php echo $rec['picture'];?>" width="100" height="100"/>
<input name="picture" type="file" value="">
</p>

Answer 1

Just a quick guess by looking at your code, you are not escaping the value of $picture when you place it in the database, which could be why the image value in the database is not updating.
Also, don't use if(!isset($_POST['picture'])), but try if (!isset($_FILES['picture']) || (isset($_FILES['picture']) && $_FILES['picture']['name'] == ""). The $_POST super global won't work, because files are sent via the $_FILES super global.
Putting it all together:
$file_name = $_FILES['picture']['name'];
$tmp_name = $_FILES['picture']['tmp_name'];
if (!isset($_FILES['picture']) || (isset($_FILES['picture']) && $_FILES['picture']['name'] == "")) {
$res = mysql_query("UPDATE student SET `id`='$id',`branch_id`='$branch_id',`class_id`='$class_id',`section_id`='$section_id',`roll_number`='$roll_number',`student_name`='$student_name',`father_name`='$father_name',`dob`='$dob',`student_address`='$student_address',`gender`='$gender',`status`='$status',`picture`='$picture',updated=now() WHERE id='$id'") or die(mysql_error());
} else {
copy($tmp_name, "images/" . $file_name)
$picture = mysql_real_escape_string("images/".$file_name);
$res = mysql_query("UPDATE student SET `id`='$id',`branch_id`='$branch_id',`class_id`='$class_id',`section_id`='$section_id',`roll_number`='$roll_number',`student_name`='$student_name',`father_name`='$father_name',`dob`='$dob',`student_address`='$student_address',`gender`='$gender',`status`='$status',updated=now() WHERE id='$id'") or die(mysql_error());
}
Also, I REALLY recommend that you use the MySQLi extension: http://php.net/manual/en/book.mysqli.php
The above code is totally untested, but should work.