How can I send HTML mail when a new content is created with attachments using these modules?
First you need to create a Rule to send a HTML email via Mimemail:


Once you've configured the rule correctly and have entered your HTML email content, you need to ensure the correct mail system class is being used by Drupal to send your emails:



If you don't select the MimeMail class within these settings, the default Drupal mail system will be uses and your HTML emails will be sent in plain text.