feat: update desktop workflows and app center

resources/skills/local/image-search/SKILL.md

@@ -8,6 +8,23 @@ Use this skill when the user needs images from the web.
 
 This skill is independent from OpenClaw's `web_search` provider configuration. Do not change Tavily, Brave, DuckDuckGo, or SearXNG settings to use this skill.
 
+## Source Priority
+
+Always prefer image sources in this order:
+
+1. Pixabay
+2. Pexels
+3. Unsplash
+4. Generic web image fallback
+
+The script uses Pixabay/Pexels/Unsplash official APIs when the matching API key is configured. If no key is configured, it still searches those sources first through site-limited image search, then falls back to generic web image results.
+
+Optional API key environment variables:
+
+- `PIXABAY_API_KEY`
+- `PEXELS_API_KEY`
+- `UNSPLASH_ACCESS_KEY`
+
 ## Standard Workflow
 
 1. Search for image candidates:
@@ -26,6 +43,7 @@ node ~/.openclaw/skills/image-search/scripts/search-images.mjs "<query>" --count
    - `results[].imageUrl` is the original image URL.
    - `results[].thumbnailUrl` is the preview image.
    - `results[].sourcePageUrl` is the page where the image came from.
+   - `results[].sourceProvider` shows whether the result came from `pixabay`, `pexels`, `unsplash`, or fallback search.
    - `results[].localPath` exists only when `--download` succeeds.
 
 4. When using downloaded images in a PPT, Word file, report, or design task, use `localPath`.