PHP: Image to base64 string

<title>Image to Base64 String</title>
<fieldset>
    <legend>Image to Base64 String</legend>
        <center>
        <form name="select_all">
                 <?php 
                /** 
 *   This code will help you to learn how we can convert an image into a base64 string!! 
 */ 
                    echo"<h3><p>Image</p></h3>"; 
                    //$file = File Image yang ingin di encode  
                    //Filetype: JPEG,PNG,GIF 
                    $file = "encode.jpg"; 
                    if($fp = fopen($file,"rb", 0)) 
                    { 
                    $gambar = fread($fp,filesize($file)); 
                    fclose($fp); 

                     
                    $base64 = chunk_split(base64_encode($gambar)); 
                    //Result 
                    $encode = '<img src="data:image/jpg/png/gif;base64,' . $base64 .'" >'; 
                    echo $encode; 
                    }     
                ?> 
                <br><textarea name="text_area" rows="20" cols="70"> <? echo $encode; ?> </textarea>
                <p><input type="button" value="Select All Code" onClick="javascript:this.form.text_area.focus();this.form.text_area.select();"></p>
        </form>
        </center>
    </fieldset>