diff --git a/src/parts/helper_functions.jl b/src/parts/helper_functions.jl
index 34b2d48b37c1372634e1c4e2b93d079e9e3c012b..0158769759ed85b74d0b7c7b3c00176259e7e42b 100644
--- a/src/parts/helper_functions.jl
+++ b/src/parts/helper_functions.jl
@@ -267,7 +267,14 @@ function interpret_image_size(fov, resolution, voxel_size, slice_thickness)
     getxy(v::Union{Tuple, AbstractVector}) = [v[1], v[2]]
     getxy(v) = [v, v]
 
-    return (slice_thickness, getz(resolution), (fov=getxy(fov), resolution=getxy(resolution), voxel_size=getxy(voxel_size)))
+    fov=getxy(fov)
+    resolution=getxy(resolution)
+    voxel_size=getxy(voxel_size)
+    if all(isnothing.(voxel_size))
+        return (slice_thickness, getz(resolution), (resolution=resolution, fov=fov))
+    else
+        return (slice_thickness, getz(resolution), (resolution=resolution, voxel_size=voxel_size))
+    end
 end
 
 end
\ No newline at end of file