Attached images are not shown in RoundCube

Symptoms

1. Attached images are not shown in RoundCube;
2. Images could be downloaded by pressing the Download button. However, they could not be opened on the filesystem;

3. When trying to view an image with enabled firebug (F12 button in a browser) the following errors appear:

   Resource interpreted as Document but transferred with MIME type image
   

   or

   Image cannot be displayed because it contains errors

4. Hexes of the sent and downloaded images differs: the downloaded one has some additional bytes at the beginning of the file:

   # xdd sent_file
   0000000: 2f75 7372 2f6c 6962 3634 2f6c 6962 6462

   # xdd downloaded_file
   0000000: 6173 6461 730a 6461 7378 6361 730a 6661
   0000010: 7364 660a 2f75 7372 2f6c 6962 3634 2f6c

Cause

Syntax error in one of the RoundCube's scripts.

Resolution

Check all customized ".php" scripts in /usr/share/psa-roundcube/. If it is possible, compare the installed RoundCube with the test one. Try to find additional closing tags, carriage returns etc.