How can I tell if an output stream is finished?

I have a page that resizes an image to be included in a html page, using: echo "<img src=\"$rel_mapfile\" alt=\"Course Map\">\n"; unlink($rel_mapfile); I need the other html stuff on the page so I need to fetch a file from the server to include in the page. So, I resized the image and saved it as a file. That works fine. After sending the temporary resized file I want to delete it. Obviously, an unlink($rel_mapfile) is executed before the echo "<img src=\"$rel_mapfile\" ... is finished. Thanks....