Thank you for writing to Aspose support team.
Aspose.Email deals all the images/contents in the body as linked resources which can then be rendered to various output formats including HTML.
1. The following code sample converts the message to HTML with linked resources embedded inside the HTML as Base64 data.
MailMessage msg = MailMessage.Load(“Input.msg”);
2. The following code sample doesn't include the linked resources embedded to the output HTML.
options.EmbedResources = false;
Thank you Kashif, it solved my case.