4/10
It's not bad, but I can't help thinking the image could be better cropped/positioned. I would go for a more dramatic ratio- cutting about half off the width and making the focal/centrepoint the girl's hand would be interesting, but I'd advise some CSS magic to arrange the text alongside the image. Keeping it simple, you could again cut about half off the image but this time lengthwise, again making the centrepoint the girl's hand. Then you could keep the text as it is, though maybe customize the font colour to match a bit more with the image. It's not bad as it is, but it's not spot-on. Also, the second line of text could be dropped down to size one to achieve a better effect there.
I really just think that the closer the ratio of an image is to 1:1, the bulkier it looks at bigger sizes. It's especially hard to pull off as a signature when you've got other things to include there- it just completely upsets the flow.