From 41ffc2c5ac3b12aa7fa982163600b50062af7184 Mon Sep 17 00:00:00 2001
From: pubpub-zz <4083478+pubpub-zz@users.noreply.github.com>
Date: Tue, 26 Sep 2023 20:11:46 +0200
Subject: [PATCH] BUG: images property fails if NullObject in list (#2215)

Discovered while working on #2214
---
 pypdf/_page.py       | 3 +++
 tests/test_images.py | 5 +++--
 2 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/pypdf/_page.py b/pypdf/_page.py
index 32720992a..520d71653 100644
--- a/pypdf/_page.py
+++ b/pypdf/_page.py
@@ -83,6 +83,7 @@
     NullObject,
     NumberObject,
     RectangleObject,
+    StreamObject,
 )
 
 MERGE_CROP_BOX = "cropbox"  # pypdf<=3.4.0 used 'trimbox'
@@ -509,6 +510,8 @@ def _get_ids_image(
 
         x_object = obj[PG.RESOURCES][RES.XOBJECT].get_object()  # type: ignore
         for o in x_object:
+            if not isinstance(x_object[o], StreamObject):
+                continue
             if x_object[o][IA.SUBTYPE] == "/Image":
                 lst.append(o if len(ancest) == 0 else ancest + [o])
             else:  # is a form with possible images inside
diff --git a/tests/test_images.py b/tests/test_images.py
index 2f14c7b38..9e03c9f35 100644
--- a/tests/test_images.py
+++ b/tests/test_images.py
@@ -12,8 +12,8 @@
 import pytest
 from PIL import Image, ImageChops, ImageDraw
 
-from pypdf import PdfReader
-from pypdf._page import PageObject
+from pypdf import PageObject, PdfReader
+from pypdf.generic import NameObject, NullObject
 
 from . import get_data_from_url
 
@@ -218,4 +218,5 @@ def test_loop_in_image_keys():
     url = "https://github.com/py-pdf/pypdf/files/12309492/example_134.pdf"
     name = "iss2077.pdf"
     reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+    reader.pages[0]["/Resources"]["/XObject"][NameObject("/toto")] = NullObject()
     reader.pages[0].images.keys()