Don't make a PNG thumbnail if the PDF creation failed.
-rw-r--r-- 17992 COPYING
-rw-r--r-- 2417 README
-rwxr-xr-x 22 cat-into
-rw-r--r-- 417 config.pm
-rwxr-xr-x 6152 createpdf.pl
-rw-r--r-- 4689 index.html
-rwxr-xr-x 2012 last.pl
-rw-r--r-- 531 pdfweb.css