diff --git a/CHANGES.rst b/CHANGES.rst
index 3cebdf9..6533dca 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -7,6 +7,7 @@ Changes
 * Drop support for Django-4.1 and earlier.
 * Add support for Django-5.1.
 * Experimental support for animated image formats. See documentation for more infos.
+* Fix #642: Do not scale images (SVG) without size information.
 
 
 2.9 (2024-07-25)
diff --git a/easy_thumbnails/processors.py b/easy_thumbnails/processors.py
index 8bb81bb..7f7ba20 100644
--- a/easy_thumbnails/processors.py
+++ b/easy_thumbnails/processors.py
@@ -215,9 +215,15 @@ def scale_and_crop(im, size, crop=False, upscale=False, zoom=None, target=None,
     target_x, target_y = [int(v) for v in size]
 
     if crop or not target_x or not target_y:
-        scale = max(target_x / source_x, target_y / source_y)
+        scale = max(
+            1.0 if source_x == 0 else target_x / source_x,
+            1.0 if source_y == 0 else target_y / source_y,
+        )
     else:
-        scale = min(target_x / source_x, target_y / source_y)
+        scale = min(
+            1.0 if source_x == 0 else target_x / source_x,
+            1.0 if source_y == 0 else target_y / source_y,
+        )
 
     # Handle one-dimensional targets.
     if not target_x:
diff --git a/easy_thumbnails/tests/test_svg_processors.py b/easy_thumbnails/tests/test_svg_processors.py
index bfafc66..f8f160c 100644
--- a/easy_thumbnails/tests/test_svg_processors.py
+++ b/easy_thumbnails/tests/test_svg_processors.py
@@ -31,6 +31,10 @@ def test_scale(self):
         self.assertEqual(upscaled.size, (1000, 750))
         self.assertEqual(upscaled.getbbox(), (0, 0, 800, 600))
 
+        empty = processors.scale_and_crop(create_image(size=(0, 0)), (1000, 1000))
+        self.assertEqual(empty.size, (0, 0))
+        self.assertEqual(empty.getbbox(), (0, 0, 0, 0))
+
     def test_crop(self):
         image = create_image()
 
@@ -49,3 +53,9 @@ def test_crop(self):
         upscaled = processors.scale_and_crop(image, (1000, 1000), crop=True, upscale=True)
         self.assertEqual(upscaled.size, (1000, 1000))
         self.assertEqual(upscaled.getbbox(), (100, 0, 600, 600))
+
+        empty = processors.scale_and_crop(
+            create_image(size=(0, 0)), (1000, 1000), crop=True
+        )
+        self.assertEqual(empty.size, (0, 0))
+        self.assertEqual(empty.getbbox(), (0, 0, 0, 0))