Chinese characters in mail received by iPhone and iPad

Hello.

I have created a template to send a mailing. To include a clickable image (let's say with a link), I have put it in a public page in Sharepoint. Then, from Explorer I copy it and paste in the mail editor. After saving, I send it and everything works fine except for that users with iPhone or iPad instead of the image receive a large number of chinese characters. Obviously seems a codification issue but I don't know how to solve it.

Any hel will be much appreciated.

Regards.