Ok let's see..
First, CHS stores all images that it captures from the clipboard as normal files in a special directory.
When you open up the CHS window and view an image clip, you see the image and a special toolbar above the image with command buttons that are specific to images:
One of those buttons will open a graphic editor on the image. Another will open the folder of images so you can browse, manage, etc.
If you click the edit button, the image will be opened in your image editor and any settings will be saved to the file -- and when CHS copies this image to the clipboard it will use your modified file.
So that's the general information. To answer your questions more directly: Screenshot Captor is still not perfectly ideal for editing random files, but you can configure it (or any other graphic editor) to be the program that CHS uses when you ask to edit an image; you'll find that setting on the "Image Capture" tab of CHS.
One more tip: CHS does not update a clip image preview automatically after you edit it -- youll have to switch away from the clip and come back to see any changes you made to the image file while the clip was still being shown in CHS. That's something i'll try to fix soon.