用 Nano Banana 2.1 為 side project 生成主視覺圖片、圖示及 OG 卡片

Every side project hits the same wall right before launch: the code works, but the landing page has no images. Here is the workflow I use to generate a consistent asset set with nanobanana21pro.com, an independent third-party web app built on Google's Nano Banana image models.

Disclosure: nanobanana21pro.com is not a Google product and not Google AI Studio. It is a separate service, not affiliated with or endorsed by Google. Writing prompts is free; generating images uses credits.

1. Write an asset spec before any prompt

Treat images like any other dependency. I keep a small spec file in the repo:

brand:
  palette: ["#0F172A", "#38BDF8", "#F8FAFC"]
  style: "soft 3D clay, rounded shapes, studio lighting"
assets:
  - id: hero
    ratio: "16:9"
    size: 2K
  - id: feature-icons
    count: 3
    ratio: "1:1"
    size: 1K
  - id: og-card
    ratio: "1.91:1 (closest available)"
    size: 1K

The point is to reuse the same style string in every prompt, so the set looks like it belongs together.

2. Generate the hero first

The hero sets the visual language. Example prompt:

Soft 3D clay illustration of a small rocket made of stacked code brackets,
launching from a laptop keyboard, navy background (#0F172A),
sky blue accents (#38BDF8), studio lighting, lots of empty space on the left
for a headline. No text.

Two tips:

• Ask for empty space where your headline will sit.
• Say "No text" when the HTML will carry the copy.

3. Use the hero as a reference for everything else

This is where reference editing pays off. Nano Banana 2.1 accepts up to 14 reference images, so I attach the approved hero and give it a role:

Use the reference image only for style, color palette and lighting.
Create a single soft 3D clay icon of a padlock on a plain #F8FAFC background,
centered, 1:1. No text.

Repeat for each feature icon (padlock, lightning bolt, chart). Because the hero is the style reference, the icons stay on-brand.

4. OG card with real text

For social preview cards I do want text in the image, and this is an area where the 2.1 model is strong at legible lettering:

Use the reference image for style and palette.
Wide social preview card, the words SHIPKIT in bold white letters on the left,
the tagline "Deploy in one command" below it in smaller sky blue letters,
the clay rocket on the right.

Keep text short and quote it exactly. Check every letter before you ship it.

5. Budget the run

The generator shows a credit quote before you submit. On Nano Banana 2.1:

My set above (one 2K hero, three 1K icons, one 1K OG card, plus a few retries) fits in a small credit pack. One-time packs start at $2.99, and monthly plans are $18.99/mo and $44.99/mo. Batch size multiplies the cost, so explore at 1K.