How can I generate AI product photos for email hero images?

Quick Answer

Render the hero at the proportions your email template uses. Most ESPs render a 600 pixel wide content column, so generate at 1200 pixels wide for retina (16:9 or 1.91:1 for a banner, 1:1 for a square card, 4:5 for a portrait), export as JPEG at 80-90% quality to stay under roughly 200KB, and brief the image with an off-center focal point so headline copy and the CTA fit over negative space. Verify the mobile crop, since the majority of email opens happen on phones. In Nightjar, aspect ratio, resolution, and output format are explicit settings on the Create form, so you can dial in email specs per send and reuse the same setup across campaigns and flows.

Specs That Match How Email Clients Render

Email clients are not browsers. A few constraints decide what the hero should be:

The mobile-first part matters because most opens happen on phones. A composition that reads at desktop width but collapses into an unreadable crop on a 375px screen is the most common failure mode. Preview the hero in your ESP's mobile preview, and if the product or headline disappears, the focal point is wrong.

Briefing the Image for Text Overlay

Email heroes almost always carry copy: a headline, a subhead, sometimes a CTA button rendered as a button in HTML on top of the image. That means the brief is different from a PDP shot. The image needs an intentional empty region.

The simplest rule: place the product on the rule-of-thirds intersection opposite the copy. If the headline sits on the left, anchor the product to the lower-right third. If the headline sits below the image, leave headroom at the top.

In Nightjar, this lives in two places. The first is the Composition, which is Nightjar's reusable arrangement that controls framing, camera angle, product placement, and crop, separate from the photographic style. Pick a Composition that already biases the product off-center. The second is Custom Directions, the plain-English instructions layered on top of the selected ingredients, where you write something like "place the product in the lower-right third, leave the upper-left two-thirds clean for text overlay."

For dark-mode clients, brief a deliberate non-white background. A soft neutral or a brand color reads correctly whether the email body is light or dark. Pure white is the format that breaks most often.

Campaigns, Flows, and ESP Workflow

Campaign images and flow images have different lifespans, and that should change how you brief them.

• Campaigns are one-off broadcast sends: a Black Friday hero, a new-product launch, a Mother's Day banner. The image runs once. Iteration speed matters more than reuse, so generate two or three candidates with Nightjar's image count control and ship the strongest.
• Flows are automated sequences: welcome series, abandoned cart, post-purchase, win-back. The image renders for months across thousands of triggers. Consistency matters more than novelty. Save the setup as a Recipe, which is Nightjar's saved Create-form configuration covering photographic style, composition, model, background, aspect ratio, resolution, and output format, so the next flow image inherits the same look without rebuilding the brief.

The handoff to Klaviyo, Mailchimp, or another ESP is a download-then-upload step. Generate the image in Nightjar, download the Asset from the Library at the target resolution and format, and upload to the ESP's image block or asset manager. There is no direct sync, so the file size and dimensions you pick at generation time are what the recipient sees.

For brands running many sends, the practical pattern is one Recipe per email format (banner hero, square card, portrait card) and one Photography Style and Composition per campaign family, so a seasonal push or a flow refresh stays visually coherent across the whole sequence.