Especially since I wasn't expecting it.
The PHPBB forums suggested a while back that the server probably didn't have the GD package. But the screenshot script uses GD funcs for cropping, resizing, stamping and saving images. Its also listed under phpinfo()
Another more recent topic discussed sending content / headers to the browser before a type 'png' header. Something possibly buried in the miscellaneous include files. A very painfull search of many includes; and nothing found.
It wasn't until I actually pasted the image URL into the browser that it displayed a missing file error on one of the include scripts.
It was that simple
