How to insert a non - database field in table.

Hi,
I have table with 3 ths.

 <th>Username</th> <th>Password</th> <th>Avatar(User's Image)</th>

.
I am using the PHP Server side scripting. I also wanna display the images in the table.

If I pass the empty space for the images field, its not processing at all.

$aColumns = array( 'username', 'password', ' ');

How to display the user's images within the table td.


Please help me to solve this issue.