OK, I'm going to go ahead and use this as an example for others who may read this later on.
Sig pics can be no larger than 468 width X 60 height px size or 19.5kb. This means it's better to have pics that are wider than taller for the sig pic, so that the pic doesn't take up many lines of the signature space allowance (hence the 60 px height size)
The OP's original pic was actually taller than wider, so when you scale it down to fit the parameters, you would get this:
So, as you can see, it makes the pic almost too hard to see any important detail keeping it to a 60px height..
However, I cropped the pic, taking out the unneccessary top and bottom extra which also now made the pic wider than taller as it should be, and got this
If this is what you like, I'll add it back to your sigline.
EDIT: I did go ahead and add it, but can take it back off.