diff --git a/openflexure_microscope/captures/capture.py b/openflexure_microscope/captures/capture.py
index ecee9462..5c840454 100644
--- a/openflexure_microscope/captures/capture.py
+++ b/openflexure_microscope/captures/capture.py
@@ -348,7 +348,7 @@ class CaptureObject(object):
         if thumbnail:
             return io.BytesIO(thumbnail)
         # If no thumbnail exists, serve the full image
-        return self.data.getvalue()
+        return self.data
 
     def save(self) -> None:
         """Write stream to file, and save/update metadata file"""