Email Signature Banner Size

A signature banner is the promotional image below the contact details, and its size decides whether it looks sharp, loads quickly, and fits on a phone. The common display width is 500 to 600 pixels, matching the roughly 600 pixel content width most email layouts use; anything wider can force horizontal scrolling or be scaled unpredictably. Height is usually 100 to 200 pixels, since a banner taller than the contact block above it overwhelms the signature, and a very tall banner pushes the actual message out of view on mobile. Export the image at twice the display size, for example 1200 by 300 pixels for a 600 by 150 banner, and set the display width in the HTML so it stays crisp on high-density screens. Keep the file under about 100 KB, using JPEG for photographic banners and PNG for flat graphics with text. Text inside the banner should be large enough to read when the banner shrinks on a phone screen, and the key message should also appear in the alt text, since many recipients see the banner with images off at first. A banner should link to one specific landing page, ideally with UTM parameters so clicks can be measured.