If you are say in an office and have 25 Dell Optiplex .... then this is completely fine, and completely legal.
HOWEVER, if these are different computers with different hardware this is not going to work well.
When windows is installed it installs itself around the hardware in the computer. If there is a minor difference between hardware (say 2 different computers both with z170 motherboards but one from ASUS and one from MSI) then you can probably be find just updating drivers; but if you say have a skylake intel on one and a haswell intel on another or even worse an AMD cpu on another then IF it even boots it will likely be unstable.
Now if you are in the situation of the first example then yes you can use any disk imaging software to put your C drive onto an external or usb (or even a newtork share if software supports it), then you load your bootable version of the clone software and your image file and image the computer.