For the moment you cannot modify or select the name.
One solution would be to save your catalog to XML and edit it manually with a text editor (notepad, ...) while renaming manually the picture files.
what i'm doing now is importing external pic, then saving and linking from within AMC (saves me from re-typing the title)...
I'm thinking to do a script to change the xml picture field with the title one (formated to fit what I want), then export pictures with title names and multi-rename...
Not possible currently.
It will probably be added in version 3.5
I will soon start to post "test"/"alpha" versions of 3.5 so people can follow the development of it.
So when I will add picture control through script you'll be able to test it