I admit I didn’t think about, let’s say, university providing access to BIL for all its faculty and students.

As with most online journal and databases, the primary model for student access is insitutional subscription. For a few thousand dollars an institution can provide access to Biology Image Library for all of its faculty and many thousands of students.

See http://www.biomedcentral.com/info/libraries/pricing?product=bil for institutional pricing information.