diff --git a/.github/mergify.yml b/.github/mergify.yml
index 14222db1094..63508de3428 100644
--- a/.github/mergify.yml
+++ b/.github/mergify.yml
@@ -4,6 +4,7 @@ pull_request_rules:
       - "#approved-reviews-by>=1"
       - label=automerge
       - status-success=Lint
+      - status-success=Typing Successful
       - status-success=Test Successful
       - status-success=Docker Test Successful
       - status-success=Windows Test Successful
diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
index e2f8bf47ac4..f9325a9eefb 100644
--- a/.github/workflows/lint.yml
+++ b/.github/workflows/lint.yml
@@ -28,5 +28,3 @@ jobs:
         uses: astral-sh/setup-uv@v7
       - name: Lint
         run: uvx --with tox-uv tox -e lint
-      - name: Mypy
-        run: uvx --with tox-uv tox -e mypy
diff --git a/.github/workflows/typing.yml b/.github/workflows/typing.yml
new file mode 100644
index 00000000000..bb4bd90190c
--- /dev/null
+++ b/.github/workflows/typing.yml
@@ -0,0 +1,52 @@
+name: Typing
+
+on: [push, pull_request, workflow_dispatch]
+
+permissions: {}
+
+env:
+  FORCE_COLOR: 1
+  PREK_COLOR: always
+  RUFF_OUTPUT_FORMAT: github
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  typing:
+    runs-on: ubuntu-latest
+
+    strategy:
+      fail-fast: false
+      matrix:
+        python-version: [
+          "3.14",
+          "3.13",
+          "3.12",
+          "3.11",
+          "3.10",
+        ]
+
+    name: Typing Python ${{ matrix.python-version }}
+    steps:
+      - uses: actions/checkout@v6
+        with:
+          persist-credentials: false
+      - uses: actions/setup-python@v6
+        with:
+          python-version: "3.x"
+      - name: Install uv
+        uses: astral-sh/setup-uv@v7
+      - name: Typing
+        run: uvx --with tox-uv tox -e mypy -- --python-version=${{ matrix.python-version }}
+
+  success:
+    permissions:
+      contents: none
+    needs: typing
+    runs-on: ubuntu-latest
+    name: Typing Successful
+    steps:
+      - name: Success
+        run: echo Typing Successful
diff --git a/Tests/test_image.py b/Tests/test_image.py
index 32c79919595..1e0377c0a05 100644
--- a/Tests/test_image.py
+++ b/Tests/test_image.py
@@ -202,7 +202,7 @@ class FP(io.BytesIO):
                 from collections.abc import Buffer
 
                 def write(self, data: Buffer) -> int:
-                    return len(data)
+                    return len(bytes(data))
 
             else:
 
diff --git a/pyproject.toml b/pyproject.toml
index cc616bc547c..82428974c2d 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -214,7 +214,6 @@ testpaths = [
 ]
 
 [tool.mypy]
-python_version = "3.10"
 pretty = true
 disallow_any_generics = true
 disallow_untyped_defs = true
diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index 76a0d4ab99f..b1c7485ab49 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -1189,6 +1189,7 @@ class Collector(BytesIO):
         data = []
 
         def write(self, data: Buffer) -> int:
+            data = bytes(data)
             self.data.append(data)
             return len(data)