max size of tmp file

What tmp file?
Your host will have a folder called /tmp/ on most unix systems, which PHP can again in most systems write to which is exactly what it says a temporary storage location.

Some caching systems, also write temporary files to wp-uploads folder?

Or it maybe something totally unrelated to WordPress

Hi Tim,

I am talking about this one:
https://postimg.org/image/x2fpd26e1/

Thanks.

Stéphane.

that appears to be a picture of a WordPress install, do you mean the tmp folder at the top which is unopen?

Some hosting systems have a /tmp directory on their setups, which is used for PHP sessions. These tend to clean themselves up over time, but if they don’t, you can clear them yourself.

That was my question. I can delete all the files then which are in this directory?
(yes it is a screenshot of my ftp)

Are there any files in there you want to keep?

WordPress does not use sessions, and it does not use a /tmp directory. So we really can’t answer your question, because we have no idea what is using those files or what created them. It was not WordPress, that’s all we can tell you.