I think you got it almost right. The distinction is between Software and other Media (Images, Sounds). The Software has to be free because otherwise it could wo

I think you got it almost right. The distinction is between Software and other Media (Images, Sounds). The Software has to be free because otherwise it could work against you (oversimplification). 'Source code' is misleading since, depending on how the artist produces the media, it technically might have source code without being user-run software (think vector grafics, MIDI with notes and synthesizer values, etc).