How to change resolution.
/etc/X11/xorg.conf (create if not exist)
# xorg.conf (X.Org X Window System server configuration file)
# This file was generated by dexconf, the Debian X Configuration tool, using
# values from the debconf database.
# Edit this file with caution, and see the xorg.conf manual page.
# (Type "man xorg.conf" at the shell prompt.)
# This file is automatically updated on xserver-xorg package upgrades *only*
# if it has not been modified since the last upgrade of the xserver-xorg
# Note that some configuration settings that could be done previously
# in this file, now are automatically configured by the server and settings
# here are ignored.
# If you have edited this file but would like it to be automatically updated
# again, run the following command:
# sudo dpkg-reconfigure -phigh xserver-xorg
Identifier "Configured Video Device"
Identifier "Generic Monitor"
HorizSync 30 - 71
VertRefresh 50 - 160
Identifier "Default Screen"
Device "Configured Video Device"
Monitor "Generic Monitor"
Modes "1280x1024" "1440x900" "1280x960" "1360x768" "1024x768" "800x600"
restart gdm and go to Monitor configuration, voila!