Thank you for your input Gordon! I appreciate the feedback. To answer your question: better alternatives are 1. to be aware that one solution for one email program is not necessarily good practice for another program especially when working with custom built code. 2. Using <td> with in-line styles has been the go-to method of producing favorable outcomes in the majority of email clients. 3. and, thank you @remi for this reminder: we use doctype in our code to render proper table stacks, so using a <td> tag is a better option over <th> for that reason.
Microsoft actually replaces the image with a 19x19 png of the entity you designate in the alt tag, and your img width value will resize it to its specifications - hence the big blow out. I tried pasting an emoji in the alt tag and the same thing happened. I also placed an icon from the Mac 'command + control + spacebar' symbol bank and they seemed to render fine.