Grandad wrote:

Hi
I need to insert a logo in my signature and don't want anyone to be able to
edit or copy it etc. Can anyone help?

When YOU get an e-mail, just how has anyone prevented YOU from doing
whatever you want with the content of that e-mail? It's on their
property, not yours. Once sent, it is no longer under your control.
You'll will find it very difficult to enforce the common-law copyright
when publicly distributing an image for which you haven't bothered to
actually file a copyright.