diff --git a/kallithea/templates/changeset/diff_block.html b/kallithea/templates/changeset/diff_block.html
--- a/kallithea/templates/changeset/diff_block.html
+++ b/kallithea/templates/changeset/diff_block.html
@@ -75,7 +75,7 @@
         </div>
         <div class="no-padding panel-body" data-f_path="${h.safe_unicode(cs_filename)}">
             ${diff|n}
-            %if cs_filename.rsplit('.')[-1] in ['png', 'gif', 'jpg', 'bmp']:
+            %if op and cs_filename.rsplit('.')[-1] in ['png', 'gif', 'jpg', 'bmp']:
               <div class="btn btn-image-diff-show">Show images</div>
               %if op == 'M':
                 <div id="${id_fid}_image-diff" class="btn btn-image-diff-swap" style="display:none">Press to swap images</div>
diff --git a/kallithea/tests/functional/test_files.py b/kallithea/tests/functional/test_files.py
--- a/kallithea/tests/functional/test_files.py
+++ b/kallithea/tests/functional/test_files.py
@@ -765,3 +765,19 @@ class TestFilesController(TestController
                                    'Successfully deleted file %s' % posixpath.join(location, filename))
         finally:
             fixture.destroy_repo(repo.repo_name)
+
+    def test_png_diff_no_crash_hg(self):
+        self.log_user()
+        response = self.app.get(url('files_diff_home',
+                                    repo_name=HG_REPO,
+                                    f_path='docs/theme/ADC/static/documentation.png',
+                                    diff1='tip', diff2='tip'))
+        response.mustcontain("""<pre>Binary file</pre>""")
+
+    def test_png_diff_no_crash_git(self):
+        self.log_user()
+        response = self.app.get(url('files_diff_home',
+                                    repo_name=GIT_REPO,
+                                    f_path='docs/theme/ADC/static/documentation.png',
+                                    diff1='master', diff2='master'))
+        response.mustcontain("""<pre>Binary file</pre>""")