Return empty dict if capture is corrupt

openflexure_microscope/camera/capture.py

@@ -49,6 +49,7 @@ def pull_usercomment_dict(filepath):
         exif_dict = piexif.load(filepath)
     except InvalidImageDataError:
         logging.error("Invalid data at {}. Skipping.".format(filepath))
+        return {}
     if 'Exif' in exif_dict and 37510 in exif_dict['Exif']:
         return yaml.load(exif_dict['Exif'][37510].decode())
     else: