It also will look in the registry for the Gimp executable and calculate the path to the command-line version.
Scheme's hard to batch to the console due to nuances with quotes as can be observed here, but it's possible. The gimp-console-.exe uses a language called 'scheme' for command interpretation.
Does anybody know how to use the gimp-console-.exe program to batch convert images between formats (with default settings) in Windows ?