diff --git a/docs/.vuepress/config.js b/docs/.vuepress/config.js
index 29fe101..0ed1fc6 100644
--- a/docs/.vuepress/config.js
+++ b/docs/.vuepress/config.js
@@ -36,7 +36,7 @@ module.exports = ctx => ({
   head: [
     ['link', { rel: 'icon', href: '/assets/images/favicon.ico', sizes: '48x48'}],
     ['link', { rel: 'icon', href: '/assets/images/favicon.svg', sizes: 'any', type: 'image/svg+xml'}],
-    ['link', { rel: 'apple-touch-icon', href: '/assets/images/apple-touch-icon.svg'}],
+    ['link', { rel: 'apple-touch-icon', href: '/assets/images/apple-touch-icon.png'}],
     ['meta', { name: 'viewport', content: 'width=device-width, initial-scale=1'}],
     ['meta', { name: 'description', content: 'Team Collaboration Software using markdown'}],
     ['meta', { name: 'keywords', content: 'markdown, wiki, javascript, react, growi, crowi'}],
diff --git a/docs/.vuepress/public/assets/images/apple-touch-icon.png b/docs/.vuepress/public/assets/images/apple-touch-icon.png
index 8ebc52d..ba88704 100644
Binary files a/docs/.vuepress/public/assets/images/apple-touch-icon.png and b/docs/.vuepress/public/assets/images/apple-touch-icon.png differ
diff --git a/docs/.vuepress/public/assets/images/ogp-logo.png b/docs/.vuepress/public/assets/images/ogp-logo.png
index 68ab464..5d1f3c8 100644
Binary files a/docs/.vuepress/public/assets/images/ogp-logo.png and b/docs/.vuepress/public/assets/images/ogp-logo.png differ