When uploading an image in wordpress, got a “Missing a temporary” error?

This is because php needs a temp folder for uploading (e.g. upload_tmp_dir in php.ini ). Usually it is just /tmp on linux/unix systems.

We encountered this error as we are running our webserver Nginx in chroot mode (see our other post on how to chroot Nginx) and in the choot, there is no /tmp folder. to fix

$ cd /opt/nginx-1.2.6
$ mkdir tmp
$ cmod 777 tmp