Improve handling of inlined images in incoming emails

lib/email/receiver.rb

@@ -194,7 +194,7 @@ module Email
       end
 
       markdown, elided_markdown = if html.present?
-        markdown = HtmlToMarkdown.new(html, keep_img_tags: true).to_markdown
+        markdown = HtmlToMarkdown.new(html, keep_img_tags: true, keep_cid_imgs: true).to_markdown
         markdown = trim_discourse_markers(markdown)
         EmailReplyTrimmer.trim(markdown, true)
       end
@@ -573,8 +573,14 @@ module Email
           upload = Upload.create_for(options[:user].id, tmp, attachment.filename, tmp.size, opts)
           if upload && upload.errors.empty?
             # try to inline images
-            if attachment.content_type.start_with?("image/") && options[:raw][/\[image: .+ \d+\]/]
-              options[:raw].sub!(/\[image: .+ \d+\]/, attachment_markdown(upload))
+            if attachment.content_type.start_with?("image/")
+              if options[:raw][attachment.url]
+                options[:raw].sub!(attachment.url, upload.url)
+              elsif options[:raw][/\[image:.*?\d+[^\]]*\]/i]
+                options[:raw].sub!(/\[image:.*?\d+[^\]]*\]/i, attachment_markdown(upload))
+              else
+                options[:raw] << "\n\n#{attachment_markdown(upload)}\n\n"
+              end
             else
               options[:raw] << "\n\n#{attachment_markdown(upload)}\n\n"
             end

spec/components/email/receiver_spec.rb

@@ -302,14 +302,22 @@ describe Email::Receiver do
       expect(topic.posts.last.raw).to eq("This is a reply :)\n\n<details class='elided'>\n<summary title='Show trimmed content'>&#183;&#183;&#183;</summary>\n---Original Message---\nThis part should not be included\n</details>")
     end
 
-    it "supports attached images" do
+    it "supports attached images in TEXT part" do
       SiteSetting.queue_jobs = true
 
       expect { process(:no_body_with_image) }.to change { topic.posts.count }
       expect(topic.posts.last.raw).to match(/<img/)
 
       expect { process(:inline_image) }.to change { topic.posts.count }
-      expect(topic.posts.last.raw).to match(/Before\s+<img.+\s+After/m)
+      expect(topic.posts.last.raw).to match(/Before\s+<img.+>\s+After/)
+    end
+
+    it "supports attached images in HTML part" do
+      SiteSetting.queue_jobs = true
+      SiteSetting.incoming_email_prefer_html = true
+
+      expect { process(:inline_image) }.to change { topic.posts.count }
+      expect(topic.posts.last.raw).to match(/\*\*Before\*\*\s+<img.+>\s+\*After\*/)
     end
 
     it "supports attachments" do