Email banners and headers: the design rules for the inbox's first inch
The header banner is the first thing every recipient sees. Dimensions and retina rules, static versus animated, and keeping fifty campaigns coherent.
The email banner, the designed header image at the top of a campaign, occupies the most reliably seen pixels in email marketing: above the fold in every client, loaded before any scrolling decision. It is also where design budgets quietly die, because every campaign needs one, they all must match the brand, and by campaign thirty the designer is recoloring the same rectangle on a treadmill.
The technical rules
- Width 600 to 640 CSS pixels, the standard email body width, exported at 2x (1200 to 1280 actual) so retina screens render crisply.
- Height with restraint: 150 to 250 CSS pixels. Taller heroes push the message below the fold on mobile, where most opens happen.
- Weight under about 200KB for a static header; the whole email's image budget matters for clipping and load, the same math as GIFs in email.
- Alt text always, because image-off is a real default in corporate inboxes, and a banner whose alt text is "banner" wastes its slot.
- Live text stays HTML. The banner carries brand and mood; the subject-critical words belong in real text that renders with images blocked.
Static or animated?
Animated headers, as GIFs, are the highest-visibility motion slot in email: a subtle brand movement, a product rotating, a sale's numbers ticking. The rules compound: first frame complete (Outlook), loop calm and short, weight within budget. The honest guidance is selective animation, the launch email, the sale opener, not every Tuesday newsletter; motion that appears on every send stops being an event.
The fifty-campaign problem
One banner is a design task; a year of campaigns is a system task. The failure mode is drift: each banner made fresh, slightly off-palette, slightly different type, until the inbox archive looks like five different brands. The system answer is the same brand-kit logic as everywhere else in this blog: lock palette, type, and layout once, then generate per-campaign variants, headline and product swapped, design constant. Email banners, static and animated, are among the flattest, most templatable assets our engine renders, and the Klaviyo integration is where they will land directly in the sending tool. The waitlist below is the queue.