better is a autostart script...
#!/bin/bashSave it as autostart, or autostart.sh, and store it under Autostart folder in your home directory.
xrandr --output VGA1 --mode "1280x800_75.00" &
Make this script executable, right click, properties, permissions, Make the file executable.
If you use LXDE, then save it in a another place, maybe ~/.local/share/autostart.
Now generate a desktop file aka
and save it in autostart folder.
Logout/in, and it should work.
The best on this script is, you can add other commands as sample a old command (not longer needed)
wbar -bpress -above-desk -vbar -pos left &