Hmm, I can't really think of any reason for login to fail. So you did a clean install of PellMon on a fresh raspbian install? That of course rules out any upgrade problems. Possibly you might have some kind of error in the configuration file, pellmon is not yet that tolerant of errors in the configuration file. You can still get pellmonsrv to crash from errors in the configuration file, possibly pellmonweb too.
The silo level graph will show up as a broken link if the silo level plugin is not running, does this line '- INFO - activated plugin SiloLevel ' show up in the event log?
Which branch did you install? The featue/processimage branch should be quite stable but it's a bit old. I merged it back to feature/websockets and continued development of the websocket use there, but it's not ready for merging to develop yet, let alone to master.
You could try shutting down both daemons with
sudo service pellmonsrv stop
sudo service pellmonweb stop
and then run them in debug mode from your source checkout in /src:
sudo ./debugsrv.sh
and in a second terminal
sudo ./debugweb.sh
(these 'quick debug' scripts work if you have installed PellMon, they use the config file from /etc/PellMon.. and they make use of the SYSTEM dbus so you have to start them with sudo so they can su to the correct system users that have permissions set up for SYSTEM bus use)
Possibly some helpful errors are shown, if not you could add some 'print' statements here and there.
About the sd card error, if you haven't done that it's a good idea to set up pellmon to use a ramdisk when running on an sd card, there is a guide on the wiki:
https://github.com/motoz/PellMon/wiki/H ... perry%20Pi , then at least PellMon will be easy on the sd card but of course there could be others who write too often.
Anyway, cool that the system image works! When this feature is ready there need to be at least a parameter with path/to/picture.svg, so you can modify the parameter to use your own picture. Maybe a couple of default pictures could be added also, with some selection of extra stuff around the boiler.