diff --git a/src/content/index.ts b/src/content/index.ts
index 50febc6a..432cf9e5 100644
--- a/src/content/index.ts
+++ b/src/content/index.ts
@@ -67,16 +67,19 @@ const elementIdTocontentId = (id: string) => {
 const main = () => {
   const target = document.getElementById('page')
   if (!target) return
+
+  let postBtnFlag = false
   const observer = new MutationObserver((mutations) => {
     for (const mutation of mutations) {
-      // 対象のElementが見つかるまでループ
-      if ((mutation.target as HTMLElement).className.includes('content-block')) {
-        // 投稿ページ全体一括保存ボタン作成
+      // 投稿ページ全体一括保存ボタン作成
+      if (!postBtnFlag && (mutation.target as HTMLElement).className.includes('post-btns')) {
         const postBtnEl = document.getElementsByClassName('post-btns')
-        if (postBtnEl.length > 0) {
-          injectPageAllContentsDlBtn((postBtnEl[0] as HTMLElement))
-        }
+        injectPageAllContentsDlBtn((postBtnEl[0] as HTMLElement))
+        postBtnFlag = true
+      }
 
+      // 対象のElementが見つかるまでループ
+      if ((mutation.target as HTMLElement).className.includes('content-block')) {
         // ギャラリーの一括保存ボタン作成
         const galleryElements = document.getElementsByClassName('content-block type-photo-gallery ng-scope')
         for (let i = 0; i < galleryElements.length; i++) {
diff --git a/src/content/modules/postPage.ts b/src/content/modules/postPage.ts
index c40f88c7..6722b472 100644
--- a/src/content/modules/postPage.ts
+++ b/src/content/modules/postPage.ts
@@ -19,8 +19,15 @@ export const downloadEverythingFromPost = async (): Promise<void> => {
 
   const baseFilepath = `${idAndTitlePath(data.fanclub.id, data.fanclub.fanclub_name_with_creator_name)}/${idAndTitlePath(data.id, data.title)}`
 
+  if (data.thumb.original) {
+    // サムネイル画像がある場合
+    const ext = data.thumb.original.split('.').at(-1)
+    fileDownload(data.thumb.original, baseFilepath, `thumbnail.${ext}`)
+  }
+
   if (data.comment) {
     // リード文がある場合
+    // TODO: リード文に埋め込まれた画像をダウンロードできるようにblog_commentをパースしてダウンロードできるようにする
     const text = `data:text/plain;charset=UTF-8,${data.comment}`
     fileDownload(text, baseFilepath, 'text.txt')
   }