diff --git a/CHANGES.md b/CHANGES.md
index 4092e15..d33aa7e 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,8 @@
+## Unreleased
+
+* Added `tinify.Format` constants for the media types `convert` accepts.
+* Added the missing `image/jpg` media type to the `convert` type hints.
+
 ## 1.7.2
 
 * Add JXL to supported image types
diff --git a/test/unit/tinify_format_test.py b/test/unit/tinify_format_test.py
new file mode 100644
index 0000000..7bc693e
--- /dev/null
+++ b/test/unit/tinify_format_test.py
@@ -0,0 +1,60 @@
+# -*- coding: utf-8 -*-
+import json
+import pytest
+
+import tinify
+from tinify import Format, Source
+
+
+class TestTinifyFormat:
+    def test_should_expose_supported_media_types(self):
+        assert Format.WEBP == "image/webp"
+        assert Format.PNG == "image/png"
+        assert Format.JPEG == "image/jpeg"
+        assert Format.JPG == "image/jpg"
+        assert Format.AVIF == "image/avif"
+        assert Format.JXL == "image/jxl"
+        assert Format.ANY == "*/*"
+
+    def test_should_not_be_instantiable(self):
+        with pytest.raises(TypeError):
+            Format()
+
+
+class TestTinifyFormatConvert:
+    @pytest.fixture(autouse=True)
+    def setup(self, mock_requests):
+        tinify.key = "valid"
+        mock_requests.post(
+            "https://api.tinify.com/shrink",
+            status_code=201,
+            headers={"Location": "https://api.tinify.com/some/location"},
+        )
+        self.mock_requests = mock_requests
+        yield
+
+    def test_convert_with_format_should_serialize_media_type(self):
+        self.mock_requests.post(
+            "https://api.tinify.com/some/location",
+            status_code=200,
+            content=b"converted file",
+        )
+
+        Source.from_buffer("png file").convert(type=Format.JXL).to_buffer()
+
+        body = json.loads(self.mock_requests.last_request.text)
+        assert body["convert"] == {"type": "image/jxl"}
+
+    def test_convert_with_multiple_formats_should_serialize_media_types(self):
+        self.mock_requests.post(
+            "https://api.tinify.com/some/location",
+            status_code=200,
+            content=b"converted file",
+        )
+
+        Source.from_buffer("png file").convert(
+            type=[Format.JXL, Format.WEBP]
+        ).to_buffer()
+
+        body = json.loads(self.mock_requests.last_request.text)
+        assert body["convert"] == {"type": ["image/jxl", "image/webp"]}
diff --git a/tinify/__init__.py b/tinify/__init__.py
index 9fcbd45..686a3cd 100644
--- a/tinify/__init__.py
+++ b/tinify/__init__.py
@@ -138,6 +138,7 @@ def from_url(url):  # type: (str) -> Source
 
 from .version import __version__
 
+from ._format import Format
 from .client import Client
 from .result_meta import ResultMeta
 from .result import Result
@@ -146,6 +147,7 @@ def from_url(url):  # type: (str) -> Source
 
 __all__ = [
     'Client',
+    'Format',
     'Result',
     'ResultMeta',
     'Source',
diff --git a/tinify/_format.py b/tinify/_format.py
new file mode 100644
index 0000000..fd9e6ce
--- /dev/null
+++ b/tinify/_format.py
@@ -0,0 +1,42 @@
+# -*- coding: utf-8 -*-
+from __future__ import absolute_import, division, print_function, unicode_literals
+
+
+class Format(object):
+    """Media types that images can be converted to.
+
+    Use these constants with :meth:`Source.convert`::
+
+        tinify.from_file("input.png") \\
+            .convert(type=tinify.Format.JXL) \\
+            .to_file("output.jxl")
+
+    Multiple types may be supplied, in which case the API returns the
+    smallest result::
+
+        .convert(type=[tinify.Format.JXL, tinify.Format.WEBP])
+    """
+
+    #: WebP.
+    WEBP = "image/webp"
+
+    #: PNG.
+    PNG = "image/png"
+
+    #: JPEG.
+    JPEG = "image/jpeg"
+
+    #: JPEG, an alias of :attr:`JPEG`.
+    JPG = "image/jpg"
+
+    #: AVIF.
+    AVIF = "image/avif"
+
+    #: JPEG XL.
+    JXL = "image/jxl"
+
+    #: Wildcard, returns the smallest of the supported types.
+    ANY = "*/*"
+
+    def __init__(self):
+        raise TypeError("Format is a namespace of constants and cannot be instantiated")
diff --git a/tinify/_typed.py b/tinify/_typed.py
index fc1a6da..06789e4 100644
--- a/tinify/_typed.py
+++ b/tinify/_typed.py
@@ -5,7 +5,7 @@ class ResizeOptions(TypedDict,total=False):
     width: Optional[int]
     height: Optional[int]
 
-ConvertTypes = Literal['image/webp', 'image/jpeg', 'image/png', "image/avif", "image/jxl", "*/*"]
+ConvertTypes = Literal['image/webp', 'image/jpeg', 'image/jpg', 'image/png', "image/avif", "image/jxl", "*/*"]
 class ConvertOptions(TypedDict, total=False):
     type: Union[ConvertTypes, List[ConvertTypes]]