Sending html emails with images inside

If the images are external image links that can be accessed by http url, then nothing speical needs to be done.

If the images are external image files, then you have 2 choices.

Embed the images as base64 strings. . This is simple. However email clients such as gmail will refuse to render them

Using cid. This is the most robust way. An example can be found here . In addition, you should set the content type of the image body part as "image/png", otherwise the email receipients will see there are attachments

     
              MimeBodyPart imagePart = new MimeBodyPart();
                DataSource fds = new FileDataSource(imageFile);
                imagePart.setDataHandler(new DataHandler(fds));
                imagePart.setHeader("Content-ID", "<" + imageFile.getName() + ">");
                imagePart.setHeader("Content-Type", "image/png");