How to increase max upload size for piwigo

Getting more confused by the hour, unfortunately. I decided that I had duped my self into thinking piwigo had created a folder on the NAS by using their own pLoader app, and populated it with a few photos. It appears not, as I could not see the folder using filezilla, and when I tried synch-ing it using the piwigo tools|synch menu nothing happens and the galleries folder is still reported as empty. I have used another of S-P's plugins (PHPSysInfo for ReadyNAS) to confirm mysqld process is running on the NAS, so I uninstalled piwigo and started again. Same problems with the new installation :cry: . What I can't get my head around is that filezilla cannot see the ./galleries folder that piwigo says is produced by installing the app in the first place. It's probably some kind of root permissions thing, but the piwigo website assumes quite a high level of technical open source knowledge, which I do not possess.
It's probably obvious that I'm still a newbie at this, and I should probably stick to 'childrens toys' such as vanilla Windows applications, but we all have to start from a baseline - it just so happens that mine is quite low :oops:. Any help from those in the know would be greatfully received.