Sending mail with embedded image in Ruby - ruby-on-rails

Question

I want to send a mail with an attached image and embed this image in html. As a source for tag , What should I write and is there any missing header parts such a content_type ?
When I am doing real test, I send to a mail to my gmail account. I can see there is an attachment with name "unnamed" and I could not display image even when I download.
Gem: Pony
require 'pony'
Pony.override_options = { :via => :test }
Pony.mail(
:to => 'foo#bar',
:from => 'abc#abc.com',
:subject => 'test123',
:body => "<h1><strong>Dear X, check the newsletter ,<br></strong></h1> <img src='attached image' />",
:attachments => {"happy_image.jpg" => File.read("happy_image.jpg")}
)
puts Mail::TestMailer.deliveries
output:
Date: Tue, 06 Dec 2016 17:23:05 +0300
From: abc#abc.com
To: foo#bar
Message-ID: <5846c9ca183d6_5983c9fd899060#MW7BIQ12TKYHQC.mail>
Subject: test123
Mime-Version: 1.0
Content-Type: multipart/mixed;
boundary="--==_mimepart_5846c9caf15a_5983c9fd8989e5";
charset=UTF-8
Content-Transfer-Encoding: 7bit
----==_mimepart_5846c9caf15a_5983c9fd8989e5
Content-Type: text/plain;
charset=UTF-8
Content-Transfer-Encoding: 7bit
<h1><strong>Dear X, check the newsletter ,<br></strong></h1> <img src='' />
----==_mimepart_5846c9caf15a_5983c9fd8989e5
Content-Type: image/jpeg;
filename=happy_image.jpg
Content-Transfer-Encoding: base64
Content-Disposition: attachment;
filename=happy_image.jpg
Content-ID: <happy_image.jpg#MW7BIQ12TKYHQC>
/9j/4AAQSkZJRgABAQEAYABgAAD/2wBDAAMCAgMCAgMDAwMEAwMEBQgFBQQE
BQoHBwYIDAoMDAsKCwsNDhIQDQ4RDgsLEBYQERMUFRUVDA8XGBYUGBIUFRT/
2wBDAQMEBAUEBQkFBQkUDQsNFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQUFBQU
FBQUFBQUFBQUFBQUFBQUFBQUFBQUFBT/wAARCAHiAuMDASIAAhEBAxEB/8QA
HwAAAQUBAQEBAQEAAAAAAAAAAAECAwQFBgcICQoL/8QAtRAAAgEDAwIEAwUF
BAQAAAF9AQIDAAQRBRIhMUEGE1FhByJxFDKBkaEII0KxwRVS0fAkM2JyggkK
FhcYGQ==
----==_mimepart_5846c9caf15a_5983c9fd8989e5--

Answer 1

You should be able to BASE64 encode the image, and use the resulting string as the src of the img tag.
For example:
<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAWQAAAD8CAYAAAB..."/>
Also make sure that your content type is set as text/html instead of text/plain. Looking at the mail, it seems that it's set to the latter, hence why images don't render and tags render as text. Add the following to your arguments to use text/html content type:
:headers => { 'Content-Type' => 'text/html' }