Add lazy_load option to participant avatar helper

app/helpers/projects_helper.rb

@@ -21,11 +21,14 @@ module ProjectsHelper
     classes = %W[avatar avatar-inline s#{opts[:size]}]
     classes << opts[:avatar_class] if opts[:avatar_class]
 
-    image_tag(avatar_icon(author, opts[:size]), width: opts[:size], class: classes, alt: '')
+    avatar = avatar_icon(author, opts[:size])
+    src = opts[:lazy_load] ? nil : avatar
+
+    image_tag(src, width: opts[:size], class: classes, alt: '', "data-src" => avatar)
   end
 
   def link_to_member(project, author, opts = {}, &block)
-    default_opts = { avatar: true, name: true, size: 16, author_class: 'author', title: ":name", tooltip: false }
+    default_opts = { avatar: true, name: true, size: 16, author_class: 'author', title: ":name", tooltip: false, lazy_load: false }
     opts = default_opts.merge(opts)
 
     return "(deleted)" unless author

app/views/shared/issuable/_participants.html.haml

@@ -11,7 +11,7 @@
   .hide-collapsed.participants-list
     - participants.each do |participant|
       .participants-author.js-participants-author
-        = link_to_member(@project, participant, name: false, size: 24)
+        = link_to_member(@project, participant, name: false, size: 24, lazy_load: true)
   - if participants_extra > 0
     .hide-collapsed.participants-more
       %a.js-participants-more{ href: "#", data: { original_text: "+ #{participants_size - 7} more", less_text: "- show less" } }