Add image to signature

[Andrea Filippini]

Hi everyone,
I have tried to add an image to signature but I can't figure out.
I have used also html code but the image doesn't appear.
The image is basically a logo with a height of 20 px (almost the same of Apple logo in signature).
Can somebody help me?
Thank you.

 

[Apple_Robert]

You can't add an image to your signature. The option has been turned off.

 

[Andrea Filippini]

You can't add an image to your signature. The option has been turned off.

I understand.
Thank you.