ENH: add decode_as_image() to ContentStreams

docs/user/extract-images.md

@@ -19,3 +19,26 @@ for image_file_object in page.images:
         fp.write(image_file_object.data)
         count += 1
 ```
+
+# Other images
+
+Some other objects can contain images, such as stamp annotations.
+
+For example, this document contains such stamps:
+
+[test_stamp.pdf](https://github.com/user-attachments/files/15751424/test_stamp.pdf)
+
+you can extract the image from the annotation with the following code
+
+```python
+from pypdf import PdfReader
+
+reader = PdfReader("test_stamp.pdf")
+im = (
+    reader.pages[0]["/Annots"][0]
+    .get_object()["/AP"]["/N"]["/Resources"]["/XObject"]["/Im4"]
+    .decode_as_image()
+)
+
+im.show()
+```

tests/test_images.py

@@ -442,7 +442,7 @@ def test_inline_image_extraction():
     img = Image.open(BytesIO(get_data_from_url(url, name=name)))
     assert image_similarity(reader.pages[0].images[0].image, img) == 1
 
-    
+
 @pytest.mark.enable_socket()
 def test_extract_image_from_object(caplog):
     url = "https://github.com/py-pdf/pypdf/files/15176076/B2.pdf"
@@ -455,10 +455,10 @@ def test_extract_image_from_object(caplog):
     with pytest.raises(Exception):
         co = reader.pages[0].get_contents()
         co.decode_as_image()
-    assert "does not seems to be an Image" in caplog.text
+    assert "does not seem to be an Image" in caplog.text
     caplog.clear()
     co.indirect_reference = "for_test"
     with pytest.raises(Exception):
         co = reader.pages[0].get_contents()
         co.decode_as_image()
-    assert "does not seems to be an Image" in caplog.text
+    assert "does not seem to be an Image" in caplog.text