I am trying to echo the following:

PHP Code:
echo "<td>" "<img src=\"" $_SERVER['DOCUMENT_ROOT'] . "/uploads/" $file_base_name "\"" "alt=\"" $row2['filename'] . "\"" "/>" "</td>"
Which should display an image in the table cell. I can confirm that the variables $file_base_name and $row_table2['filename'] are filled -- I've echoed each independently and got the desired results.

The above code produces:
<td><img src="example.com/uploads/" alt="" /></td>
Variables after $_SERVER['DOCUMENT_ROOT'] are not being interpreted, and I don't know why.