Fix checking image link

htmlproofer/plugin.py

@@ -116,9 +116,10 @@ def on_post_page(self, output_content: str, page: Page, config: Config) -> None:
 
         all_element_ids = set(tag['id'] for tag in soup.select('[id]'))
         all_element_ids.add('')  # Empty anchor is commonly used, but not real
-        for a in soup.find_all('a', href=True):
-            url = a['href']
 
+        urls = set(a['href'] for a in soup.find_all('a', href=True)) | set(img['src'] for img in soup.find_all('img'))
+
+        for url in urls:
             if any(fnmatch.fnmatch(url, ignore_url) for ignore_url in self.config['ignore_urls']):
                 if self.config['warn_on_ignored_urls']:
                     log_warning(f"ignoring URL {url} from {page.file.src_path}")

tests/unit/test_plugin.py

@@ -108,6 +108,21 @@ def test_on_post_page__plugin_disabled():
     plugin.on_post_page('<a href="https://google.com"><a/>', Mock(spec=Page), Mock(spec=Config))
 
 
+def test_on_post_page__img():
+    plugin = HtmlProoferPlugin()
+    plugin.load_config({
+        'validate_rendered_template': True,
+        'raise_error': True,
+    })
+    page = Mock(
+        spec=Page,
+        file=Mock(spec=File, src_path='blah.md'),
+        content='',
+    )
+    with pytest.raises(PluginError):
+        plugin.on_post_page('<img src="not-existing.png" />', page, Mock(spec=Config))
+
+
 @pytest.mark.parametrize(
     'url',
     (