nano-banana special prompt achieved rapid Mobile UI Mockups

#ai #nanobanana #gemini #uidesign

TL;DR

Use Gemini 2.5 Flash Image (a.k.a "nano-banana") to generate a single figure with exactly four iPhone screens showing a left‑to‑right user journey. A copy‑paste prompt blueprint is included below, along with three ready‑made customizations (Fitness, Cooking, Finance). Iterate lightly by adjusting theme, contrast, and density, keeping backgrounds minimal, and labeling each screen.

I recently dove into mobile app development and quickly ran into a familiar early-stage hurdle: turning fuzzy ideas into concrete UI directions. Traditional approaches like paper sketches, wireframes, or Figma all work well, but each comes with a learning curve and setup time. For quick ideation on layout, flow, and visual tone, without opening a design tool, Google’s Gemini 2.5 Flash Image (a.k.a “nano-banana”) is a surprisingly capable partner.

In this article, I’ll share a prompt-first workflow for generating high-quality, consistent, four-screen iOS mockups that communicate a complete user journey. You’ll get a copy‑paste prompt blueprint you can reuse, three ready‑made customizations (Fitness, Cooking, Personal Finance), and practical tips to tune outputs while avoiding common pitfalls.

This isn’t a replacement for proper product design. It’s a fast, visual way to explore directions, align with stakeholders, and then hand off to Figma or code with more confidence.

What is “nano-banana”?

Gemini 2.5 Flash Image (“nano-banana”) is Google’s image-generation model released in late August 2025.

It’s optimized for speed and consistency, and it does especially well with structured prompts that describe layout, device framing, and content constraints.

You can use nano-banana in Google AI Studio:

https://aistudio.google.com/

Why a prompt-first mockup?

A prompt-first approach delivers speed to clarity, producing realistic screens in minutes that are ideal for brainstorming and stakeholder conversations. It has low overhead because you can explore concepts without setting up design files or libraries. It also encourages journey‑first thinking by forcing clarity on the flow rather than on isolated screens, and it’s repeatable since a structured prompt makes results consistent and easy to iterate.

The 4‑screen mockup prompt blueprint

Use the following prompt to generate a single image with four iPhone screens laid out horizontally, telling a left‑to‑right user journey. Replace the bracketed fields with your app’s details.

<Create a professional iOS app mockup figure>
showing exactly 4 iPhone screens arranged horizontally in a single high-resolution image. The screens demonstrate a complete user journey for a [Application Type] application.

<APP SPECIFIC CUSTOMIZATION>
Application Core: [User Input of application core]
Primary Features:
1. [User Input of feature 1, example: Dashboard]
2. [User Input of feature 2, example: Figure]
3. [User Input of feature 3, example: Charts]
4. [User Input of feature 4, example: Log]
Visual Theme: [User Input of Theme, example: Energetic orange and black theme, bold sans-serif typography, high contrast design, motivational imagery]
Target Audience: [User Input of audience, example: Aged 20-40]
<END CUSTOMIZATION>

DETAILED VISUAL SPECIFICATIONS:
Device Frame: Modern iPhone 15/16 Pro Max with Dynamic Island, edge-to-edge display, no home button
Screen Resolution: High-quality, crisp rendering at 2796×1290 pixels per screen
Background Setting: Subtle blurred gradient or professional studio backdrop that complements the app theme
Lighting: Soft, even lighting with minimal shadows for professional presentation

UI/UX REQUIREMENTS:
Native iOS 17+ components using SwiftUI design language
System font (SF Pro) with proper typography hierarchy
Consistent spacing following Apple's Human Interface Guidelines (8pt grid system)
Interactive elements clearly distinguishable (buttons, toggles, text fields)
Proper safe areas and status bar implementation
Tab bar or navigation structure visible where appropriate
Realistic, meaningful content (no lorem ipsum) - use actual examples relevant to the app
Clear visual flow from left to right showing user progression

COMPOSITION AND STYLE:
Arrange 4 iPhone mockups in a horizontal line with equal spacing
Each screen labeled with its function at the top or bottom
Consistent color palette throughout all screens
Use depth and shadows to create professional mockup appearance
Include subtle animations indicators where relevant (like transition hints)
Show different states (empty states, filled states, active selections)

OUTPUT FORMAT:
Single cohesive figure, resolution minimum, professional presentation quality suitable for App Store submission or investor pitch deck. Photorealistic device rendering with the app screens perfectly integrated.

How to use it

Define the journey by picking four states that tell a cohesive story (for example, Overview → Details → Edit → Confirm). Fill the APP SPECIFIC CUSTOMIZATION with concrete, real content—avoid lorem ipsum entirely. Generate and assess the result by checking consistency across screens in type, spacing, colors, and data. Iterate with small edits by nudging theme, contrast, or content density and tightening typographic hierarchy. When you have a clear winner, export the figure for your deck, brief, or design kickoff.

Three ready‑to‑use customizations

1) Fitness Tracker

Use this block to replace the <APP SPECIFIC CUSTOMIZATION> section in the blueprint.

<Create a professional iOS app mockup figure>
showing exactly 4 iPhone screens arranged horizontally in a single high-resolution image. The screens demonstrate a complete user journey for a Fitness tracker application.

<APP SPECIFIC CUSTOMIZATION>
Application Core: Personal fitness tracking and workout planning application with AI coaching
Primary Features:
1. Dashboard - Daily activity summary, calories burned, steps, heart rate
2. Workout Library - Exercise videos, custom routines, difficulty levels
3. Progress Charts - Weight trends, strength gains, body measurements over time
4. Activity Log - Workout history, personal records, achievement badges
Visual Theme: Energetic orange and black theme, bold sans-serif typography, high contrast design, motivational imagery with gradient accents
Target Audience: Health-conscious individuals aged 20-40
<END CUSTOMIZATION>

2) Cooking Recipe App

Use this block to replace the section in the blueprint.

<Create a professional iOS app mockup figure>
showing exactly 4 iPhone screens arranged horizontally in a single high-resolution image. The screens demonstrate a complete user journey for a Cooking recipe application.

<APP SPECIFIC CUSTOMIZATION>
Application Core: Smart recipe organizer with meal planning and grocery list generation
Primary Features:
1. Recipe Feed - Curated daily recipes with dietary filters and seasonal suggestions
2. Meal Planner - Weekly calendar view with drag-and-drop meal scheduling
3. Shopping List - Auto-generated grocery lists organized by store sections
4. My Cookbook - Personal recipe collection with family recipes and notes
Visual Theme: Warm earth tones with sage green accents, elegant serif headers, food photography backgrounds, minimalist card-based layouts
Target Audience: Home cooks and food enthusiasts aged 25-50
<END CUSTOMIZATION>

3) Personal Finance Manager

Use this block to replace the section in the blueprint.

<Create a professional iOS app mockup figure>
showing exactly 4 iPhone screens arranged horizontally in a single high-resolution image. The screens demonstrate a complete user journey for a personal finance manager application.

<APP SPECIFIC CUSTOMIZATION>
Application Core: Smart personal finance manager with AI-powered spending insights and investment tracking
Primary Features:
1. Overview - Total balance, monthly spending summary, budget status, upcoming bills
2. Transactions - Categorized expense list with merchant logos, search and filters
3. Analytics - Spending breakdown charts, category trends, savings goals progress
4. Investments - Portfolio performance, stock watchlist, crypto holdings, market news
Visual Theme: Professional navy blue and gold accents, clean geometric patterns, financial data visualizations with glassmorphism effects, trust-inspiring design
Target Audience: Young professionals and investors aged 25-45
<END CUSTOMIZATION>

Quality tips and tuning

Keep it real by replacing placeholders with plausible, domain‑specific content such as dates, names, amounts, and imagery. Enforce hierarchy by asking for a clear typographic hierarchy using SF Pro and by constraining line lengths—for example, keep titles under 30 characters. Increase contrast if results look washed out by specifying high‑contrast, WCAG‑conscious color usage. Tighten spacing by including an 8pt grid and consistent spacing in prompts, and request more negative space if layouts feel crowded. Control density by limiting per‑screen content to six to eight distinct elements. Anchor the journey by explicitly naming each screen in the prompt and requesting labels on the mockups. Iterate lightly, changing one variable at a time—colors, data density, or component style—before regenerating.

FAQ

Why four screens?

Four is enough to show context → explore → focus → commit without overwhelming the viewer, and the format fits neatly in a wide figure for decks.
In addition, Generative AI has less capability to make consistency when generating separate images.

When to use nano‑banana vs. a design tool

Use nano‑banana for early ideation and alignment when you need fast, realistic visuals to explore directions, align stakeholders, or kick off discussions without opening Figma or Sketch. It especially shines when you want to present a left‑to‑right user flow (onboarding → browse → detail → act) in one cohesive figure.

For specs and interactivity, move to Figma/Sketch/XD for component specs, typography tokens, responsiveness, and interactive prototypes, and refer to Apple’s Human Interface Guidelines (HIG) for platform‑correct patterns and accessibility. Treat nano‑banana as a way to visualize, then validate color/contrast and touch targets against WCAG and HIG in your design tool or implementation. In short, generate to decide direction and design to solidify implementation.

Summary

Nano-banana shows new way of UI designing. Prompt‑first mockups won’t replace design systems, but they’re fantastic for momentum. Use the blueprint to frame a journey, generate credible screens, and then bring the winning direction into Figma or code.