Problem with render

Hi. I'm trying to use render to display an Image, but it's not working. My ideia is: In the field 4, if the field 8 isn't empty, show field 4 + image from field 8.

This is my code:

$(document).ready(function() {
                $('#example').dataTable( {
                    "processing": true,
                    "serverSide": true,
                    "ajax": {
                        "url": "proc_flights.php",
                        "type": "POST"
                    },
                    
                    
                    "columnDefs": [ {
                        "targets": 4,                        
                        "render": function ( data, type, full, meta ) {
                            if (full[8]!='') {                                
                                return '<img src="'+full[8]+'" />';
                            } else {
                                return data;
                            }                              
        
                        }
                      } ]
                    
                    
                    
                } );
            } );

Field 8 are returning 'TAM.png', but my brownser tries to get this URL:

http://radar.jonis.com.br/%27+full%5B8%5D+%27

If I just 'return full[8]', I got 'TAM.png' on my tables (this is correct), so the data is correct. What I'm doing wrong? I'm using XHTML.

Tks