Thank you for chiming in - I am glad someone else is speaking up on the topic.

I have reported this issue via email, the Q&A online, a poll for the new invoicing, and I have even gone so far as to call and spend HOURS on the phone with customer service desperately trying to get them to understand the issue.  I also sent screenshots and even shared my screen with someone.

I continue to have this problem STILL today.  As others mentioned, it is not the size of the graphic (S,M,L), that affects the logo in the email - that is for the invoice.  I tried what you suggested above, made a "small" logo; and still the same problem in my email.  This has been an issue now for over a year.  Thankfully, my clients have not been commenting or complaining. 

I am NOT calling customer service again as you are suggesting.  Someone needs to fix this ASAP.  PLEASE!  I want to mention, Intuit charged a 20% increase for subscription services since I joined 1 year ago, as well as a 5% increase on EFT payments, and yet we have no customer service and have to deal with unprofessional invoices. Unacceptable Intuit!!!!!!!!