diff --git a/tests/test_library_entrypoints.py b/tests/test_library_entrypoints.py
index 1ee80ff..2888249 100644
--- a/tests/test_library_entrypoints.py
+++ b/tests/test_library_entrypoints.py
@@ -329,6 +329,10 @@ class SteamGridDB(unittest.TestCase):
         self.assertEqual(set(images),set(artwork.SLOTS));self.assertEqual(warnings,[])
         self.assertTrue(all(url.endswith('/top.png') for url in images.values()))
         self.assertTrue(all('/game/2?' in p for p in calls[1:]))
+        # SteamGridDB rejects JPEG in logo/icon queries (the live API returned an error for SuperTux).
+        for p in calls[1:]:
+            jpeg = 'image%2Fjpeg' in p
+            self.assertEqual(jpeg, p.startswith(('/grids/', '/heroes/')), p)
 
     def test_unicode_titles_match_exactly_and_symbols_never_match_all(self):
         self.assertEqual(sgdb._name('ビートセイバー VR!'), 'ビートセイバーvr')
diff --git a/ui/frame_steamgriddb.py b/ui/frame_steamgriddb.py
index 017511c..6a18bba 100644
--- a/ui/frame_steamgriddb.py
+++ b/ui/frame_steamgriddb.py
@@ -84,7 +84,9 @@ def lookup(name, deadline=None):
         for slot, kind, dimensions in [('grid', 'grids', '600x900'), ('wide', 'grids', '920x430'),
                                        ('hero', 'heroes', ''), ('logo', 'logos', ''), ('icon', 'icons', '')]:
             try:
-                query = {'types': 'static', 'nsfw': 'false', 'humor': 'false', 'mimes': 'image/png,image/jpeg'}
+                # Logos and icons only come as PNG (or WebP/ICO); asking for JPEG there is rejected outright.
+                mimes = 'image/png,image/jpeg' if kind in ('grids', 'heroes') else 'image/png'
+                query = {'types': 'static', 'nsfw': 'false', 'humor': 'false', 'mimes': mimes}
                 if dimensions:
                     query['dimensions'] = dimensions
                 records = _get('/' + kind + '/game/' + str(gid) + '?' + urllib.parse.urlencode(query), key, deadline)