These tools are intended for large scale cloning in commercial environments. Their main advantage is that they only clone the used part of the drive (and ability to re-image drives across a network... OK: their two main advantages are image size, network savvy, and they look cool... three... OK - their many advantages include ... ... I'll start again!)
Anyway - dd will copy every byte, including the zeros - so the image size will be the same size as your disk. Which on the Eee is what? 4 gig?
You will be erasing the main linux install after imaging - and the image restoring programs along with it. You will need to install linux to an external drive, so the Eee can boot off it when you want linux back. (Though this is a way to have dual boot.)
If you have a usb optical drive, a live disk is doable. What's important is that the Eee drive partitions are not mounted when you image the drive.
Assuming that the Eee internal drive is /dev/sda and the storage drive partition is /dev/sde5 then (and it is formatted with a filesystem which can handle 4GiB files) then:
mount /dev/sde5 /media/usbdrive
dd if=/dev/sda of=/media/usbdrive/eee.img
Of course you modify this for your situation. Read the dd manpage for other options to refine this. Many people also want to specify the block size.
If your storage media is the same drive you booted from, then you don't need the mount part.
To put the image back, you reverse the order of the if= and of= arguments
dd if=/media/usbdrive/eee.img of=/dev/sda
You'll need to do a grubinstall if you installed windows.
That wiki site I linked to has a lot of insight into the Eee - make sure you are familiar with how it is designed to work before fiddling.
If you have more that 4 gig it that thing, well done, you should stick the dd through the tar or gzip archiver.
If you stuff up, then you can always just install a full linux. Have fun.