Build a wide email header banner. A calm gradient or soft abstract texture across the whole frame in two brand colours. Space left clear in the centre for a logo and a short line of text. Subtle depth — a soft shape or blur, nothing busy. Light enough that dark text will read over it. No fine detail: this is viewed small and often with images half-loaded.
“Use it” opens the editor with this prompt already loaded — add your photo and generate. Copy works anywhere else: ChatGPT, Gemini, Midjourney.
Email clients render images unpredictably. Keep it simple and make sure it works without the images too.