$Picture_name is the name of the file from the browse field on the form, for example, it you had
<input type="file" name="Picture">
then on php page, $Picture_name would give you whatever.jpg
$name is just getting the name from $Picture_name for reference into the database, i do this cuz with mine i put the logged persons username in front of the name so i can easily search for them later when i want to display them
so i have
$logged equal to their username, the i have
$name = $logged . "_" . $Picture_name;
i just didn't do that for you since you didn't say anything about that and thought that would confuse you more