Dear Friends, this article will teach you, how add new resolution value to your list of Resolutions

1. Goto Terminal
2. Give command :    xrandr   
then you will see a result like the screen shot given below..


3. then give the resolution with cvt command which you want to add like this,
command : cvt xxxx xxxx (eg in my case : cvt 1024 800) 
 then you will see a result like the screen shot given below...


4. then copy(shift+ctrl+c) the part "1024x800_60.00"   66.75  1024 1080 1184 1344  800 803 813 831 -hsync +vsync"
and paste it with the xrandr --newmode command like the code given below.

command(in my case) : xrandr --newmode "1024x800_60.00"   66.75  1024 1080 1184 1344  800 803 813 831 -hsync +vsync

5. then give command :    xrandr --addmode <output> <name> 

eg: xrandr --addmode default 1024x800_60.00.
....



6. then give again command :   xrandr 
now you can see new resolution in the list.
 



7. then you can add new resolution with GUI by System -> Preferences -> Display
or with the terminal
command :   xrandr --output default --mode 1024x800_60.00  

If it is not applied, restart the mechine and change the resolution to new value with  System -> Preferences -> Display ...