How do I enlarge an imported graphic signature for the digitial signature box?

I have a signature.jpg that I have used for years for the 'FILL and SIGN' option. Worked great for signing and to indicated if it was okay to pay checks, etc. You can resize it larger or smaller and place it on the page anywhere. It even got rid on the background!!!

Now we are working with a different animal. The Digital signature block...and in the "Configure Signature Appearance" box, there is a spot to configure graphics. You can choose the "No graphic'"radio button and nothing goes there, or choose the "Name" radio button and have the anme on your digital signature typed into the signature field and lastly you can select the "Imported Graphics" radio button. With the Imported Graphic, you can browse your files until you find an image of your signature.

Everything is good except when I choose my old signature, it is readable but very small. I doubled the size of the picture. Still showed the same size. I wrote my name 3 inches long by 1 inch tall as one person suggested. Still as small as the others. This doesn't seems to work like the "Fill & Sign" where you can stretch it out.

I can't seem to find an answer, except write it bigger which did not work. The last few I played with I imported as a .png with the background removed. Still no luck...

Thanks for any help!