Hello,
The provider I am using (ovh.net in France) cannot manage symlinks on some of their servers.
I thus encountered problem when cached files are symlinks to image in albums.

Is there an option to not using symlinks ?
Thanks for your help because I cannot find a solution when I search in the forum.
Sincerely

Not sure what you mean. Cached images are not symlinks to the original files in the albms.
Maybe you are confused by the URL you see?

@fretzl: Actually they are indeed symlinks if the size of cached sized images is the same size as the original so it is not doubled unnecessarily regarding disc space.

But if the server does not support/allow symlinks there should be just copies. That's the case on my own host actually.

There is no option to disable that. But you could manuelly set the constant defining it to false
/zp-core/global-definitions.php' line 35. But of course you need to re-do this on every update. Better ask your host to disable symlinks at all if it doesn't work anyway.

Thanks acrylian for your help: I have found where to set this constant manually.
Actually, on the host I am using (ovh.net), the symlink is set correctly to the original file but it appears curiously as a folder in the cache directory. So zenphoto cannot find the original file. I can't understand why... I should check with my provider.

That sounds weird indeed. Best to contact the provider. Settings on servers can be very different.