Only the web version of Bluewin currently supports email attachments with the automatic preview feature for photos, albums and files from myCloud. However, you still have the option to send the generated share links as a normal text link.
Information on how share links are handled in apps such as Bluewin, WhatsApp, Facebook, etc. can be found here.
Find out how you can send myCloud share links from your computer with email programs such as Outlook, Gmail, etc.