add support to keep img tags when converting to html

lib/email/receiver.rb

@@ -194,7 +194,7 @@ module Email
       end
 
       markdown, elided_markdown = if html.present?
-        markdown = HtmlToMarkdown.new(html).to_markdown
+        markdown = HtmlToMarkdown.new(html, keep_img_tags: true).to_markdown
         markdown = trim_discourse_markers(markdown)
         EmailReplyTrimmer.trim(markdown, true)
       end

lib/html_to_markdown.rb

@@ -6,7 +6,8 @@ class HtmlToMarkdown
     def initialize(name, head="", body="", opened=false, markdown=""); super; end
   end
 
-  def initialize(html)
+  def initialize(html, opts={})
+    @opts = opts || {}
     @doc = Nokogiri::HTML(html)
     remove_whitespaces!
   end
@@ -133,8 +134,12 @@ class HtmlToMarkdown
   end
 
   def visit_img(node)
-    title = node["alt"].presence || node["title"].presence
-    @stack[-1].markdown << "![#{title}](#{node["src"]})"
+    if @opts[:keep_img_tags]
+      @stack[-1].markdown << node.to_html
+    else
+      title = node["alt"].presence || node["title"].presence
+      @stack[-1].markdown << "![#{title}](#{node["src"]})"
+    end
   end
 
   def visit_a(node)

spec/components/html_to_markdown_spec.rb

@@ -31,8 +31,14 @@ describe HtmlToMarkdown do
     expect(html_to_markdown(%Q{<a href="https://www.discourse.org">Discourse</a>})).to eq("[Discourse](https://www.discourse.org)")
   end
 
+  HTML_WITH_IMG ||= %Q{<img src="https://www.discourse.org/logo.svg" alt="Discourse Logo">}
+
   it "converts <img>" do
-    expect(html_to_markdown(%Q{<img src="https://www.discourse.org/logo.svg" alt="Discourse Logo">})).to eq("![Discourse Logo](https://www.discourse.org/logo.svg)")
+    expect(html_to_markdown(HTML_WITH_IMG)).to eq("![Discourse Logo](https://www.discourse.org/logo.svg)")
+  end
+
+  it "keeps <img> with 'keep_img_tags'" do
+    expect(HtmlToMarkdown.new(HTML_WITH_IMG, keep_img_tags: true).to_markdown).to eq(HTML_WITH_IMG)
   end
 
   (1..6).each do |n|