First of all, select ur desired folder..
and hit "ALT+ENTER".. a properties dialog will pop up..
go to » Customize tab » Customize. There, choose any icon, click Apply and OK.

now in the address bar of ur folder.. type "\desktop.ini" before ur folder's path..
a file named "desktop.ini" will open in notepad..
just add these lines on it..


[ExtShellFolderViews]
{BE098140-A513-11D0-A3A4-00C04FD706EC}={BE098140-A513-11D0-A3A4-00C04FD706EC}
[{BE098140-A513-11D0-A3A4-00C04FD706EC}]
IconArea_Image=C:\path\folder\background.jpg


To customize this according to your needs, edit the path in the last line to reflect to the location of the image you wish to use as the background image for that folder. Refresh the folder and the new background should appear.

now, to remove the default icon chosen during the creation of the desktop.ini and restore the default folder icon, delete these lines of code from within the desktop.ini file:

[HIDE-THANKS]
[.ShellClassInfo]
IconFile=%SystemRoot%\system32\shell32.dll
IconIndex=(some number)