nice script

however i had to set the -t /tmp/* path to the home dir of the user, cause i wanna start phoenix through a script, and so the privilege management was easier.
is there a way to create bigger images? i only found the width value, but no height value. you could may add the values to the config?
If you're running from a usb thumb drive, I highly recommend putting the phoenix output to tmpfs, since writes on flash memory are limited. (btw, noticed that in stock debian6, /tmp isn't tmpfs, it just resides on disk. this is bad of usb sticks as well. you can fix this by mounting /tmp as tmpfs in fstab)
Anyway, to change the chart configuration, currently one has to edit the gen-graph.php file. In later versions I could make the rrdgraph parameters configurable via the config file. But for now, here's a quick reference from RRDtool website:
rrdgraph manpage (Scroll down to "Size" section)