diff --git a/AGENTS.md b/AGENTS.md
index cf787af..0790263 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -28,7 +28,7 @@ This is the main way people contribute. Add one shop end to end.
    }
    ```
 
-3. **Photo** — must be **under 300KB**, EXIF-stripped, longest side ~800px, named `{shopId}-001.jpg` (`-002`, … for more). Use the helper (macOS `sips` + `jpegtran`):
+3. **Photo** — must be **under 300KB**, EXIF-stripped, longest side ~800px, named `{shopId}-001.jpg` (`-002`, … for more). Use the helper (macOS `swift` + `sips` + `jpegtran`; it also applies the EXIF orientation so photos stay upright):
 
    ```sh
    mkdir -p content/shops/{shopId}
diff --git a/tools/resize.sh b/tools/resize.sh
index e7803d0..1b94cf7 100755
--- a/tools/resize.sh
+++ b/tools/resize.sh
@@ -12,6 +12,6 @@ new_path=$2
 echo "Move: $org_path to $new_path"
 mv $org_path $new_path
 echo "Resize and Optimize: $new_path"
-sips -Z 800 $new_path
+swift "$(dirname "$0")/resize.swift" $new_path $new_path
 jpegtran -copy none -optimize -outfile $new_path $new_path
 sips -g pixelHeight -g pixelWidth $new_path
diff --git a/tools/resize.swift b/tools/resize.swift
new file mode 100644
index 0000000..14e1405
--- /dev/null
+++ b/tools/resize.swift
@@ -0,0 +1,29 @@
+import Foundation
+import ImageIO
+
+let args = CommandLine.arguments
+guard args.count == 3 else {
+  FileHandle.standardError.write("Usage: swift resize.swift input.jpg output.jpg\n".data(using: .utf8)!)
+  exit(1)
+}
+
+let options = [
+  kCGImageSourceCreateThumbnailFromImageAlways: true,
+  kCGImageSourceCreateThumbnailWithTransform: true,
+  kCGImageSourceThumbnailMaxPixelSize: 800,
+] as CFDictionary
+
+guard let source = CGImageSourceCreateWithURL(URL(fileURLWithPath: args[1]) as CFURL, nil),
+  let image = CGImageSourceCreateThumbnailAtIndex(source, 0, options),
+  let destination = CGImageDestinationCreateWithURL(
+    URL(fileURLWithPath: args[2]) as CFURL, "public.jpeg" as CFString, 1, nil)
+else {
+  FileHandle.standardError.write("Failed to resize \(args[1])\n".data(using: .utf8)!)
+  exit(1)
+}
+
+CGImageDestinationAddImage(destination, image, nil)
+guard CGImageDestinationFinalize(destination) else {
+  FileHandle.standardError.write("Failed to write \(args[2])\n".data(using: .utf8)!)
+  exit(1)
+}