。
She has small feet.
Literal
She [topic-は] foot [subject-が] is-small.
Body-feature description with the [topic]は[body part]がい-adj structure — Japanese describes inherent physical features through 'X is small / large / etc. with respect to body part Y.' 足 here is more naturally read as 'feet' (since shoes-and-feet are the small-or-large topic, not legs). The [topic]+は+[body part]+が+[adjective] frame is one of the canonical Japanese grammatical patterns and shows up in everything from 頭がいい ('smart') to 目が大きい ('has big eyes').