BUG: Avoid completely hiding image loading issues like exceeding image size limits (#3221)

Closes #3220.

Author: stefan6419846

pypdf/_xobj_image_helpers.py

@@ -264,7 +264,7 @@ def _handle_flate(
         # Stream Dictionary
         mode2 = _get_imagemode(color_space, colors, mode)[0]
         if mode != mode2:
-            img = Image.frombytes(mode2, size, data)  # reloaded as mode may have change
+            img = Image.frombytes(mode2, size, data)  # reloaded as mode may have changed
     if mode == "CMYK":
         extension = ".tif"
         image_format = "TIFF"

pypdf/filters.py

@@ -840,6 +840,7 @@ def _apply_alpha(
 
     try:  # temporary try/except until other fixes of images
         img = Image.open(BytesIO(data))
-    except Exception:
+    except Exception as exception:
+        logger_warning(f"Failed loading image: {exception}", __name__)
         img = None  # type: ignore
     return extension, data, img

tests/test_filters.py

@@ -656,3 +656,19 @@ def test_ccitt_fax_decode__black_is_1():
     expected_pixels = list(ImageOps.invert(expected_image_inverted).getdata())
     actual_pixels = list(actual_image.getdata())
     assert expected_pixels == actual_pixels
+
+
+@pytest.mark.enable_socket
+def test_flate_decode__image_is_none_due_to_size_limit(caplog):
+    url = "https://github.com/user-attachments/files/19464256/file.pdf"
+    name = "issue3220.pdf"
+    reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+    images = reader.pages[0].images
+    assert len(images) == 1
+    image = images[0]
+    assert image.name == "Im0.png"
+    assert image.image is None
+    assert (
+        "Failed loading image: Image size (180000000 pixels) exceeds limit of "
+        "178956970 pixels, could be decompression bomb DOS attack."
+    ) in caplog.messages