Week 1 System Email personalisation

I've made a signature using David's template and imported it in as a png image, set left aligned (looks fine in the editor) but in the tests emails it still appears indented no matter what I do.

Q1: How do I get the signature aligning with the copy?

Q2: the system emails background is not pure white, so we need to import with transparent background? Or where do we change the system email background colour?

Thanks in advance 🙏