Library art: real gameplay instead of GitHub social cards; accept GIF sources

GitHub's opengraph preview is repo text, stats and an identicon; as a Steam hero
it looked broken. GitHub entries no longer default to it (the store draws its
fallback, Steam gets generated art). Source GIFs (common gameplay captures) are
accepted; the Frame's Chromium draws the first frame. Open Saber Plus uses its
gameplay GIF as banner. Verified on the Frame: hero/wide now show gameplay.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ui/apk_sources/github.py

@@ -35,7 +35,8 @@ def _entry(source, c, approved=True):
     artwork = c.get('images') or {}
     icon = artwork.get('icon') or c.get('icon') or 'https://github.com/' + c['repo'].split('/')[0] + '.png'
     images = {'icon': icon,
-              'banner': artwork.get('banner') or 'https://opengraph.githubassets.com/1/' + c['repo'],
+              # No GitHub social-preview card: it's repo text and stats, not art; the UI draws a fallback.
+              'banner': artwork.get('banner'),
               'screenshots': list(artwork.get('screenshots') or [])}
     return {'source': source['id'], 'id': c['repo'], 'package': None,
             'name': c['name'], 'summary': c.get('summary') or '', 'icon': icon,

ui/apk_sources/github_curated.json

@@ -9,7 +9,7 @@
     "allow_prerelease": false,
     "images": {
       "icon": "https://raw.githubusercontent.com/KhronosGroup/OpenXR-SDK-Source/3ed64d0f9bb680f24b80a085091e5c8fab38f7b7/src/tests/hello_xr/android_resources/vulkan/mipmap-xxxhdpi/ic_helloxr_launcher.png",
-      "banner": "https://opengraph.githubassets.com/1/KhronosGroup/OpenXR-SDK-Source",
+      "banner": null,
       "screenshots": []
     },
     "icon": "https://raw.githubusercontent.com/KhronosGroup/OpenXR-SDK-Source/3ed64d0f9bb680f24b80a085091e5c8fab38f7b7/src/tests/hello_xr/android_resources/vulkan/mipmap-xxxhdpi/ic_helloxr_launcher.png"
@@ -60,7 +60,7 @@
     "allow_prerelease": false,
     "images": {
       "icon": "https://raw.githubusercontent.com/arpruss/OpenSaberPlus/8c5295cdaadf02ea7418b0c6cbea20240ba913af/icon.png",
-      "banner": "https://opengraph.githubassets.com/1/arpruss/OpenSaberPlus",
+      "banner": "https://raw.githubusercontent.com/arpruss/OpenSaberPlus/8c5295cdaadf02ea7418b0c6cbea20240ba913af/doc/images/OS0.4.0_1.gif",
       "screenshots": [
         "https://raw.githubusercontent.com/arpruss/OpenSaberPlus/8c5295cdaadf02ea7418b0c6cbea20240ba913af/doc/images/OS0.4.0_1.gif",
         "https://raw.githubusercontent.com/arpruss/OpenSaberPlus/8c5295cdaadf02ea7418b0c6cbea20240ba913af/doc/images/OS0.4.0_2.gif",

ui/frame_artwork.py

@@ -34,6 +34,12 @@ def image_type(data):
     if data.startswith(PNG):
         png_size(data)
         return 'png'
+    if data[:6] in (b'GIF87a', b'GIF89a') and len(data) >= 10:
+        # Gameplay GIFs are common source screenshots; the Frame's Chromium draws their first frame.
+        w, h = struct.unpack_from('<HH', data, 6)
+        if w and h and w * h <= MAX_PIXELS and max(w, h) <= 8192:
+            return 'gif'
+        raise ValueError('artwork GIF has unsupported dimensions')
     if data.startswith(b'\xff\xd8'):
         # Check JPEG SOF dimensions without depending on an image library; trailing padding is fine.
         pos = 2
@@ -52,7 +58,7 @@ def image_type(data):
                     return 'jpg'
                 break
             pos += size
-    raise ValueError('artwork must be a supported PNG or JPEG')
+    raise ValueError('artwork must be a supported PNG, JPEG or GIF')
 
 
 def fetch(value, deadline=None):