Handwritten signature image - changing appearance when inserted

When I use the image of my handwritten signature to sign a pdf doc, it's now suddenly looking different once inserted on the document. It always looked the same on the pdf as it looks in it's saved jpg file, and if I edited the jpg - like made it lighter for example - the way it appeared once inserted on the pdf would match and it would also be lighter. Now regardless of how I edit or change the way my signature looks in the jpg file, on the pdf file it keeps looking the same - dark, dark black with thick scraggly lines. See attached side-by-side the way signature looks as a jpg on the left, and they way it looks once inserted on the pdf?? I've tried changing the settings in preferances but it doesn't make a difference. Is there a way I can make my handwritten signature look like a proper handwritten signature again?