ok, I understand that I don't must use special character but as I say on top off this topic in french language removing special character reduce readability. I use ZP as an automatic backup of my photo collection so I prefer not change directory's names. So sorry for my obstinacy...
However I think there is a little problem with ZP 1.2.8 because there is the same problem on 2 differents servers (linux apache and windows apache). And why the generation of thumbs work great and not the full view of the picture? In the cache folder there are the same special characters and it works. I don't want to be boring or insistent with you...