is it a feasible and good idea to just make an IMAGE of the Laptop
A good idea: no.
Your desktop will have different hardware and will require different drivers. While you can take an image of the old laptop, you still will have to do some installing on the new desktop. And it will likely involve sysprep or other software to remove parts from the laptop before you image it.
It will work, but you will end with all old software (good) and all old cruft (bad).
Personally I would make a clean install on the new desktop. Run all windows updates.
Then make a backup of that (for future emergency use). Next would be installation and updating of anti virus software and the copying of old files from the laptop. (Either via a network or by temporarily putting the laptop disk in an external 2½ case).
However if you go for the image solution, read up on