Import signature from image file in Preview

I'd like to sign pdfs using my signature. Unfortunately, Preview seems to require that you have a trackpad or a camera to do it. I have a Mac Mini, which has neither.

I do have my signature as a jpeg. In Acrobat on Windows, I could just import it and it worked. How do I do that in Preview?


Signatures are stored in the keychain. If you can create a signature on another machine this thread may be of use Can I export my signature from Preview on one Mac and import it on another?