Update 2

layouts/shortcodes/content.html

@@ -0,0 +1,5 @@
+<div class="row">
+  <div class="col-12 mb-50 content">
+    {{ .Inner }}
+  </div>
+</div>

layouts/shortcodes/download.html

@@ -0,0 +1,8 @@
+<div class="container">
+  <div class="card border-primary rounded-0 hover-shadow mb-5">
+    <div class="card-body">
+      <h4 class="card-title"><a href='{{ .Get "link" }}'>{{ .Get "title" }}</a></h4>
+      <a href='{{ .Get "link" }}' class="btn btn-primary btn-sm">Download</a>
+    </div>
+  </div>
+</div>

layouts/shortcodes/gallery.html

@@ -8,10 +8,10 @@ Documentation and licence at https://github.com/liwenyip/hugo-easy-gallery/
 {{ $baseURL := .Site.BaseURL }}
 <div class="gallery caption-position-{{ with .Get "caption-position" | default "bottom" }}{{.}}{{end}} caption-effect-{{ with .Get "caption-effect" | default "slide" }}{{.}}{{end}} hover-effect-{{ with .Get "hover-effect" | default "zoom" }}{{.}}{{end}} {{ if ne (.Get "hover-transition") "none" }}hover-transition{{end}}" itemscope itemtype="http://schema.org/ImageGallery">
 	{{- with (.Get "dir") -}}
-		<!-- If a directory was specified, generate figures for all of the images in the directory -->
+		<!-- If a directory was specified, generate figures for all of the media in the directory -->
 		{{- $files := readDir (print "/static/" .) }}
 		{{- range $files -}}
-			<!-- skip files that aren't images, or that inlcude the thumb suffix in their name -->
+			<!-- skip files that aren't media, or that inlcude the thumb suffix in their name -->
 			{{- $thumbext := $.Get "thumb" | default "-thumb" }}
 			{{- $isthumb := .Name | findRE ($thumbext | printf "%s\\.") }}<!-- is the current file a thumbnail image? -->
 			{{- $isimg := lower .Name | findRE "\\.(gif|jpg|jpeg|tiff|png|bmp)" }}<!-- is the current file an image? -->