You asked the question which tools I would recommend for imaging the C partition. Here is what I recommend:
A. In a normal Windows 7 installation you have to image the C partition and the 100MB System Partition which contains the bootmgr. Usually there is also a recovery partition which I would image at least once.
B. If you ever want to recover from the image, you need a recovery medium which can be a CD or a USB flash drive. I will specify what to use.
D. Imaging programs - there is a vast choice of imaging programs, but I found 2 solutions that work very well and are easy to use. They are also fast and reliable.
D1. Free Macrium Version 5 (not version 6 which is not free) is my preferred solution. Here is a tutorial I made where you find all the information required. Since this is easily overlooked in the tutorial, I give you my link from where you can download the .iso for the recovery CD/flash drive. Just burn that .iso to a CD or Flash drive and for recovery you boot the PC with that medium. You can, of course, produce that recovery medium yourself from within Macrium.
D2. Another easy way to make an image is via an elevated command prompt. The command is:
wbadmin start backup -backupTarget:X: -include:C: -AllCritical -quiet
Where 'X' is the address of the device to where you want to place the image. The '-AllCritical' parameter will make sure that the 100MB System Partition is automatically imaged with the C partition. This is unlike solution D1 where you have to explicitely select that 100MB partition to be imaged with C. The recovery from the image you can initiate with any Windows 7 installation/recovery disk.
Should you ever want to make an image of a data partition, you can use the same command, but you must leave the '-AllCritical' parameter off - else you would also image C and the whole 9 yards with that data partition.