diff --git a/cellpose/models.py b/cellpose/models.py
index 3457b0a1..8ca72483 100644
--- a/cellpose/models.py
+++ b/cellpose/models.py
@@ -243,6 +243,8 @@ def eval(self, x, batch_size=8, channels=None, channel_axis=None, z_axis=None,
                 reason = 'does not work on non-2D images'
             models_logger.warning(f'could not estimate diameter, {reason}')
             diams = self.diam_mean 
+        else:
+            diams = diameter
 
         tic = time.time()
         masks, flows, styles = self.cp.eval(x,