Group: Awaiting Activation
No, the installation and the OS are too tightly coupled, for example, with registry entries and files scattered around various places on the "C" drive. Also, imaging programs work at a lower-level and don't necessarily know anything about the files component - it is just copying disk clusters.
I don't get concerned about the OS slowing down anymore. In the days of older versions of Windows it was indeed an issue. Do you have real data, as in a stop-watch to time a task, that supports your concern?
What you could do is go back and install Windows on a clean disk without any or many apps I'd include Reflect for installation though. Then make an image which would become a base image. It probably would be good to let Windows do its updates and then make another image for a more current base of the OS. Then install the apps and configure and make another image which would become a base of your whole system.
This gives you a clean starting point if you wanted to refresh the system but you still would be looking at doing all the Windows updates and any changes to the apps and configuration since you made the base. A bit more reality, if any of the what you perceive as slowing is being caused by a Windows or app update or configuration change, you are still going to get it.