New images not shown in front end

[pereca]

Hi, 
I'm using 1.5.6.1 and suddenly, new images added for products stopped appearing in the front end.
In the back end it's visible, the picture is uploaded to the server, I have checked.
 
On the server, the picture exist in the folder e.g. img\p\2\1\0\210-large-default.jpg but on the URL http://www.direktna-trgovina.si/210-large_default/testni-produkt.jpg, the question mark picture shows.
 
 
Existing pictures on old products work OK, no changes in any settings were performed in the mean time. What the hack is wrong?
 
Thanks, Cheers,

Edited April 10, 2014 by pereca (see edit history)