Modules in the 'lib' directory

Hi, I have a module in the /myApp/lib directory to help manage image
files. It is coincidentally called ‘image_manager’.

There is a function in there called asset_path, which is used to
determine the path of the images that is defined as follows:
def asset_path

I am including the image manager module in the model for the image, but
when I call this function I get the following error:
undefined local variable or method `foo’ for #Album:0x39b0d70

“foo” is a function I have in my application controller and helper, and
is defined as follows:
def foo

Apparently the module can’t see the methods in the application
controller and helper. Is there some other way the module in ‘lib’ can
get at the object I have in my session?