I figured out finally how to delete the big signature. Now I am wondering what the size of the pic has to be in order to fit right. What are the limit for dimensions mine was 324 x 78 4.55 kb and still too big!
Usually the sizing for the signature is 50 pixels high by about 250 pixels wide. This is approximate as all signatures are a bit different. You should be able to use paint (or Photoshop) to manipulate the sizing.
Please PM me if you have any questions.