Instead of drawing border, calculate palette index before image creation in expand()

Tests/test_imageops.py

@@ -156,23 +156,31 @@ def test_scale():
     assert newimg.size == (25, 25)
 
 
-def test_expand_palette():
-    im = Image.open("Tests/images/p_16.tga")
-    im_expanded = ImageOps.expand(im, 10, (255, 0, 0))
+@pytest.mark.parametrize("border", (10, (1, 2, 3, 4)))
+def test_expand_palette(border):
+    with Image.open("Tests/images/p_16.tga") as im:
+        im_expanded = ImageOps.expand(im, border, (255, 0, 0))
 
-    px = im_expanded.convert("RGB").load()
-    for b in range(10):
+        if isinstance(border, int):
+            left = top = right = bottom = border
+        else:
+            left, top, right, bottom = border
+        px = im_expanded.convert("RGB").load()
         for x in range(im_expanded.width):
-            assert px[x, b] == (255, 0, 0)
-            assert px[x, im_expanded.height - 1 - b] == (255, 0, 0)
+            for b in range(top):
+                assert px[x, b] == (255, 0, 0)
+            for b in range(bottom):
+                assert px[x, im_expanded.height - 1 - b] == (255, 0, 0)
         for y in range(im_expanded.height):
-            assert px[b, x] == (255, 0, 0)
-            assert px[b, im_expanded.width - 1 - b] == (255, 0, 0)
+            for b in range(left):
+                assert px[b, y] == (255, 0, 0)
+            for b in range(right):
+                assert px[im_expanded.width - 1 - b, y] == (255, 0, 0)
 
-    im_cropped = im_expanded.crop(
-        (10, 10, im_expanded.width - 10, im_expanded.height - 10)
-    )
-    assert_image_equal(im_cropped, im)
+        im_cropped = im_expanded.crop(
+            (left, top, im_expanded.width - right, im_expanded.height - bottom)
+        )
+        assert_image_equal(im_cropped, im)
 
 
 def test_colorize_2color():

src/PIL/ImageOps.py

@@ -21,7 +21,7 @@ import functools
 import operator
 import re
 
-from . import Image, ImageDraw
+from . import Image
 
 #
 # helpers
@@ -395,15 +395,16 @@ def expand(image, border=0, fill=0):
     height = top + image.size[1] + bottom
     color = _color(fill, image.mode)
     if image.mode == "P" and image.palette:
-        out = Image.new(image.mode, (width, height))
-        out.putpalette(image.palette)
-        out.paste(image, (left, top))
-
-        draw = ImageDraw.Draw(out)
-        draw.rectangle((0, 0, width - 1, height - 1), outline=color, width=border)
+        image.load()
+        palette = image.palette.copy()
+        if isinstance(color, tuple):
+            color = palette.getcolor(color)
     else:
-        out = Image.new(image.mode, (width, height), color)
-        out.paste(image, (left, top))
+        palette = None
+    out = Image.new(image.mode, (width, height), color)
+    if palette:
+        out.putpalette(palette.palette)
+    out.paste(image, (left, top))
     return out