diff --git a/fsl/data/image.py b/fsl/data/image.py
index f914e10946bb6ac37bba2bdd237073736b79ff56..1eb55c413a02f23f16f7cfaa26769c77d79c2027 100644
--- a/fsl/data/image.py
+++ b/fsl/data/image.py
@@ -1179,8 +1179,8 @@ class Image(Nifti):
         data = self[sliceobj]
         data = np.array(data, dtype=dtype, copy=False)
 
-        oldShape = np.array(data.shape)
-        newShape = np.array(newShape)
+        oldShape = np.array(data.shape, dtype=np.float)
+        newShape = np.array(newShape,   dtype=np.float)
 
         if not np.all(np.isclose(oldShape, newShape)):