I want to write html image tag inside php but the below code is not working, Please help.
<?php 
....
....
echo '<img src="../admin/upload/'<?=$display_img?>" width="120px" height="120px"/>
.....
?>
    You don't need the php tags you just need to break out of the string:
$width = 120;
echo '<img src="../admin/upload/' . $display_img . '" width="' . $width . 'px" height="120px"/>';
    <? ?> when you are already in another.<?=$display_img?> the equal sign doesn't belong here and the code is attached to the php tags, so the compiler may not be able to read it. It was better this way <?php echo( $display_img ) ?>, of course if you weren't already in php.Echoing is a bit messy for me, I would've exited php first like this.
<?php
....
....
?>
<img src="../admin/upload/<?php echo( $display_img ) ?>" width="120px" height="120px"/>
<?php
.....
?>
or here is your original code corrected:
<?php 
....
....
echo '<img src="../admin/upload/' . $display_img . '" width="120px" height="120px" />';
// OR 
echo '<img src="../admin/upload/{$display_img}" width="120px" height="120px" />';
.....
?>
    echo is a statement not a function. No need for brackets.