I got a weired behavior on my apache, php setup on a debian wheezy system.
Discovered while I tried to create an image with php and output it directly. It failed permanent and the browser said sth. like corrupt image file. After a lot of try and error arround 3 hours I figured out that there is a TAB character added right at the beginning ob my image content, that does not belong there.
To proove that its part of the apache-php setup I created a test.php file, that just contains the letter 'a' and coppied this file to test.html. So Both files just contain the letter a. You can see the resulting tab here:
and even on the base url itself - its a php-file, too. Hope anybody can point me in the correct direction. Btw. on the console everything is fine: php test.php just returns an a. Maybe it is something about the Apache MimeTypes or headers in general?!