The other kind of scripting that FontCreator supports is the Complete Composites feature, which can be used in conjunction with the Transform Wizard to add multiple new glyphs with character mappings to a font, but it won’t generate new outlines from images.
The kind of macro scripting language that I imagine you’re thinking of is discussed in this feature request thread. It is on the ToDo list, but not implemented yet. I honestly don’t think there is much need for it now that we have the other automation features.
If you can generate the images with Java, drag and drop will soon get them into FontCreator, especially if you can generate Adobe Illustrator, EPS, or PDF vectors.