what I want is for Screenshot Captor to automatically save my screenshot, to my hard drive, without my having to interact with a popup dialogue box.
Good man -- this is what I always recommend to people and it was how Screenshot Captor was originally designed to function.
All you need to do is configure the "After Capture Show.." option to select "
Stay Minimized".
This option is so important that there are 3 different places you can set it: In the system tray menu, In the post-capture pop-up dialog itself if you have that currently set, and in the preferences on the "Interface Options" tab at the top.
Let me know if you have any trouble.