Hi, I have some trouble using face annotators, and I think the issue is caused by some inconsistency between feeding a batch of images vs a single image when calling the annotator. More precisely : + The FaceCrop [sends a **single image** to the annotator](https://gitlab.idiap.ch/bob/bob.bio.face/-/blob/master/bob/bio/face/preprocessor/FaceCrop.py#L349), and [expects to receive a **single dictionary of annotations**](https://gitlab.idiap.ch/bob/bob.bio.face/-/blob/master/bob/bio/face/preprocessor/FaceCrop.py#L299) + While (from my understanding) the [Base annotator](https://gitlab.idiap.ch/bob/bob.bio.face/-/blob/master/bob/bio/face/annotator/Base.py#L5) expects a **list of images** and returns a **list of annotations dictionaries** (one dictionary per provided image). I should be able to propose an easy fix, but which is the correct expected behavior ? ping @ydayer @tiago.pereira