<form name="form1" method="post">
                            <div class="form-group">
                                <label for="exampleFormControlFile1">Select a custom profile picture</label>
                                <input type="file" class="form-control-file" name ="f1" >
                                <input type ="submit" class="form-control-submit" name="submit1" value="Upload">


                            </div>
                            </form>

                            <?php
                                    if(isset($_POST["submit1"]))
                                    {

                                    $tm=md5(time());
                                    $fnm=$_FILES["f1"]["name"];
                                    $dst="./images/".$tm.$fnm;
                                    $dst1="images/".$tm.$fnm;

                                    move_uploaded_file($_FILES["f1"]["tmp_name"],$dst);


                                    $res2=mysqli_query($link,"SELECT * FROM image WHERE uid = $_SESSION[uid]");
                                    $row2 = mysqli_fetch_array($res2);

                                        if(empty($row2["image"])){
                                        mysqli_query($link,"INSERT INTO image values('$_SESSION[uid]','$dst1')");

                                    }else{
                                        mysqli_query($link,"UPDATE image SET image= '$dst1' WHERE uid = '$_SESSION[uid]' ");
                                    }


                                }
                            ?>