Email signatures: Simple text vs. big image banners; what works better?

[CarolDavis]

I'm re-designing my company email signature. Is it better to stick to plain text with a single link, or add a graphic banner promoting a sale or ebook?

 

[Luisestrada]

I'd use a simple HTML signature as the default—name, role, company, one phone number, and one primary link—because it renders reliably and is easy to scan. A small campaign banner can work, but I'd treat it as a time-limited test with alt text and a tracked URL. Avoid putting essential contact details inside the image, since some email clients block images and large banners can look overly promotional.