、。
I don't know her name, but I know her face.
Literal
Name [topic-は] not-know [but-が], her [possessive-の] face [only-だけ] [topic-は] know.
A striking contrastive: 名前は...顔だけは — two は particles stacking 'as for name' and 'as for just her face.' The だけ ('only') on 顔 narrows the known part. 知っている dropped to 知っている for state, then 知らない plain for negative. Crisp, idiomatic.