I would recommend searching this forum and also the Articles forum in this community for postings which discuss Windows 7 imaging. This is a huge topic and of course there are many different ways of deploying Windows 7 including using sysprepped images. Other factors which can determine deployment choices is whether a KMS server is present to handle licensing and activation or whether you are using a volume MAK key.
For an initial test, try imaging the entire DISK instead of a single partition. You will still need to reactivate an imaged machine since Windows 7 will easily detect that it is running on different hardware as the bios serial number and the network MAC address will be different, and of course if you use a sysprepped image, this automatically removes the licensing information as well.