Almost a year later, but will still reply for those with the same question, and stumbling upon this topic.
I had the same issue, solved it by creating a mapper. (Keycloak v24)
First add a “picture” field to the profile.
Then go to Identity Providers > Google > Mappers > Add mapper
Type: Attribute Importer
Set Id, Name, Path and User attrobute name to picutre.