Fixed bad exception type.

scripts/mouse/slice_to_volume.py

@@ -2051,7 +2051,7 @@ def match_volume_resolution(img, **kwargs):
     import imageio
     try:
         ext = imageio.formats[ext].extensions[0].lstrip(".")
-    except IndexError:
+    except KeyError, IndexError:
         ext = ts.TIMAGE_DEFAULT_SNAPSHOT_EXT
     filename = os.path.join(p.general.outputdir, f"{fn}_mrires.{ext}")
     img.snapshot(filename, overwrite=True)