TYPO3 Core

Disabling error_reporting would not fully solve this problem.
You'll also get no image displayed, if in any included file whitespaces are before/after the -tags.

You are right, but in which cases would whitespaces be included?
The main problem is the use of error_reporting in a way that no error-message would ever appear. I would suggest:

- disabling the error_reporting

or alternatively

- inform the user about the problem

Thanks Gunther

You are right, but in which cases would whitespaces be included?

For example by some extensions which does not comply the CGL. Currently we had this effect with EXT:multishop. Whitespace could also be included by faulty realurl configurations - or by any other automatically included files from outside the TYPO3 Core.

i fixed it in my installation with:

t3lib/thumbs.php:
Line 41: ob_start();
Line 404: ob_end_clean();

Maybe we can get the output-buffer and if there ist any whitespace includen, then write to some error log / error message?

After updating TYPO3 CMS 4.5.25 to 4.5.27, the generating of thumbnails in the backend stopped working. The error is reproducible on 3 different servers (CentOS 6.4, PHP 5.3.3).

By opening http://domain.tld/typo3/thumbs.php?&dummy=1369910747&file=%2Fsrv%2Fwww%2Fvhosts%2Fdomain.tld%2Fhtdocs%2Ffileadmin%2FTest%2F200.jpg&md5sum=69ec2fa10f the following error messages occured:

in Chrome: Fehler 330 (net::ERR_CONTENT_DECODING_FAILED): Unbekannter Fehler.
in Firefox: Content-Encoding-Fehler. Die Webseite, die Sie öffnen möchten, kann nicht angezeigt werden, da sie eine ungültige oder unbekannte Form der Kompression verwendet.

The error does not occur when you remove "ob_clean();" from line 206 in t3lib/thumbs.php or when you add a ob_start() somewhere before that line.

Hmm, this is weird. I tested it on a variety of servers myself. This seems to be dependent on some server configuration, but I don't know which. Already for us it solved a bug that appeared only on some servers.

Anyway you should open a separate issue and related it to this one, to give it the proper visibility.