Well, you have used some unusual options, which may make it appear as not working. For example C (put to current folder), which may be unpredictable, because it puts the file in the current folder of the current process, which may be any folder. So, I would recommend to not use it unless you know, what "current folder" is in Windows. If your goal is to overwrite the file, use I (i). Also S may cause problems as it skips the resizing if the source file is smaller.
As a side note, you are using 1200x1200, which always resizes to 1200x1200 pixels, changing aspect ratio of non-square images. There are other modes, which you may find more useful.