docs: update the docs/content pages

Document the selection orders of summary and thumbnail

exampleSite/content/docs/content/index.md

@@ -79,6 +79,28 @@ $ hugo new posts/new-post/index.zh-cn.md
 > Please remind that, the created posts are generally in draft state. You'll need to specify the `-D` parameter of the command `hugo server` for previewing.
 > Similarly, you need to change the `draft` to `false` or remove `draft` parameter if you want to publish the article.
 
+## Summary Selection Order
+
+1. If `post.excerpt = "description"` and `description` is not empty, then it'll be used.
+1. Manual splitting via <code>&lt;!--more--&gt;</code>.
+1. If `summary` on front matter isn't empty, then `summary` will be selected.
+1. The text of content will be cut off by `post.excerptMaxLength` and formatted in plain text or HTML when `post.plainifyExcerpt = ture`.
+
+```toml {title="config/_default/params.toml"}
+[post]
+  # excerpt = "description"
+  # excerptMaxLength = 120
+  # copyright = false # Whether to display copyright section on each post.
+  # plainifyExcerpt = false # Format excerpt in HTML if false.
+```
+
+## Thumbnail Selection Order
+
+1. The `images` on front matter are preferred.
+1. Page images resources that match the filename's patterns: `*feature*`, `*cover*` and `*thumbnail*`. Such as `posts/my-page/feature.png`.
+
+> The page images resources will be resized to several smaller versions to suit the users devices for saving the bandwidth.
+
 ## Pinning Posts
 
 You can pin posts on the home page by setting `pinned` to `true` on the front matter.
@@ -93,8 +115,6 @@ weight = 100
 
 > If there is multiple pinned posts, they are sorted by `weight` in descending order.
 
-### Site Parameters
-
 ```toml {title="config/_default/params.toml"}
 pinnedPost = false # Disable pinned posts globally.
 pinnedPostCount = 2 # The number of pinned posts shown on home page.

exampleSite/content/docs/content/index.zh-cn.md

@@ -77,6 +77,28 @@ $ hugo new posts/new-post/index.zh-cn.md
 
 > 请注意：创建的文章一般处于草稿状态，本地预览时，`hugo server` 需要指定 `-D` 参数才能预览草稿文章。文章发布时，需要将 `draft` 改为 `false`，或者直接移除 `draft` 参数。
 
+## Summary Selection Order
+
+1. If `post.excerpt = "description"` and `description` is not empty, then it'll be used.
+1. Manual splitting via <code>&lt;!--more--&gt;</code>.
+1. If `summary` on front matter isn't empty, then `summary` will be selected.
+1. The text of content will be cut off by `post.excerptMaxLength` and formatted in plain text or HTML when `post.plainifyExcerpt = ture`.
+
+```toml {title="config/_default/params.toml"}
+[post]
+  # excerpt = "description"
+  # excerptMaxLength = 120
+  # copyright = false # Whether to display copyright section on each post.
+  # plainifyExcerpt = false # Format excerpt in HTML if false.
+```
+
+## Thumbnail Selection Order
+
+1. The `images` on front matter are preferred.
+1. Page images resources that match the filename's patterns: `*feature*`, `*cover*` and `*thumbnail*`. Such as `posts/my-page/feature.png`.
+
+> The page images resources will be resized to several smaller versions to suit the users devices for saving the bandwidth.
+
 ## 文章置顶
 
 你可以通过在 front matter 设置 `pinned` 为 `true` 以置顶文章。

exampleSite/content/docs/content/index.zh-tw.md

@@ -77,6 +77,28 @@ $ hugo new posts/new-post/index.zh-tw.md
 
 > 請注意：創建的文章一般處於草稿狀態，本地預覽時，`hugo server` 需要指定 `-D` 參數才能預覽草稿文章。文章發佈時，需要將 `draft` 改為 `false`，或者直接移除 `draft` 參數。
 
+## Summary Selection Order
+
+1. If `post.excerpt = "description"` and `description` is not empty, then it'll be used.
+1. Manual splitting via <code>&lt;!--more--&gt;</code>.
+1. If `summary` on front matter isn't empty, then `summary` will be selected.
+1. The text of content will be cut off by `post.excerptMaxLength` and formatted in plain text or HTML when `post.plainifyExcerpt = ture`.
+
+```toml {title="config/_default/params.toml"}
+[post]
+  # excerpt = "description"
+  # excerptMaxLength = 120
+  # copyright = false # Whether to display copyright section on each post.
+  # plainifyExcerpt = false # Format excerpt in HTML if false.
+```
+
+## Thumbnail Selection Order
+
+1. The `images` on front matter are preferred.
+1. Page images resources that match the filename's patterns: `*feature*`, `*cover*` and `*thumbnail*`. Such as `posts/my-page/feature.png`.
+
+> The page images resources will be resized to several smaller versions to suit the users devices for saving the bandwidth.
+
 ## 文章置頂
 
 你可以通過在 front matter 設置 `pinned` 為 `true` 以置頂文章。