You can try writing code as:
<a href="url"><img src="source" alt="name" /></a>
Also, please use the image in JPG format because PNG image is not supported by all the email clients like Lotus.
Alternately, please share the piece of code where you have inserted the image file.
The code snippet that we shared with you yesterday can work for email as well. When you are creating the email, you can open the HTML viewer and use this code for the image.
Hopefully this should work for you.