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Image generation steps turn a text prompt into an image you can display in chat, pass to another step, or hand back as a downloadable link. Airia offers more than one image-generation step — pick the tab for the step you’re using.
💡 Displaying the result is the same idea for every step: an image step returns data (a URL or encoded bytes), not a rendered picture. To show it in the conversation, render it as markdown with a Message Formatter step placed downstream — each tab below shows the exact reference.
Nano Banana and Nano Banana Pro are image-generation steps powered by Google’s Gemini image models.
  • Nano Banana — Gemini 2.5 Flash Image. Fast generation at 1024px, with customizable aspect ratios.
  • Nano Banana Pro — Gemini 3 Pro Image. Professional quality with resolutions up to 4K (1K / 2K / 4K).
💡 Find them in Steps → Actions → Image Models → Gemini.

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Configuration

FieldApplies toDescription
CredentialBothThe Google API Key credential to use. Leave blank to use the Airia Key.
Prompt (required)BothDescribe the image to generate. Supports {{variable}} syntax, so you can build the prompt from upstream steps and user input.
Aspect RatioBoth1:1 (default), 2:3, 3:2, 3:4, 4:3, 4:5, 5:4, 9:16, 16:9, 21:9.
Image SizeNano Banana Pro only1K (~1024px, default), 2K (~2048px), 4K (~4096px).
Output FormatBothBase64 (default) — image bytes embedded in the response. Download URL — image is uploaded to blob storage and a temporary signed URL is returned.
URL ExpiryBoth (only when Output Format = Download URL)How long the URL stays valid, in minutes. 0 = environment default, a positive number = custom minutes, Perpetual = non-expiring.
💡 Choosing an Output Format: Use Download URL when you want to display or share the image (it gives you a plain link you can embed or hand to a user). Use Base64 when a downstream step needs the raw bytes inline.

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Output

Each step returns a GeminiGenerateImageResponse:
{
  "Images": [
    {
      "ImageUrl": "https://.../signed-blob-url",
      "ImageDataBase64": null,
      "MimeType": "image/png"
    }
  ],
  "Message": "…",
  "TotalCount": 1
}
  • Images[] — One entry per generated image. Each has:
    • ImageUrl — the signed download URL (when Output Format = Download URL).
    • ImageDataBase64 — the base64-encoded bytes (when Output Format = Base64).
    • MimeType — e.g. image/png.
  • Message — any text the model returned alongside the image.
  • TotalCount — number of images generated.

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Displaying the image in chat

Wire a Message Formatter step after Nano Banana:
Input  →  Nano Banana  →  Message Formatter  →  Output
  1. On the Nano Banana step, set Output Format → Download URL (and, if you want the link to stay valid, set URL Expiry → Perpetual).
  2. In the Message Formatter, use markdown’s image syntax pointing at the step’s ImageUrl: 
    ![image]({{Inputs.Nano_Banana.Output.Images[-1].ImageUrl}})
    • Inputs.Nano_Banana refers to the upstream step by its title, with spaces replaced by underscores (Nano Banana → Nano_Banana, Nano Banana 1 → Nano_Banana_1). See Variables for the naming rules.
    • .Output.Images[-1] grabs the most recently generated image ([-1] is the last item); use [0] for the first.
    • ![alt](url) is markdown’s image tag, so the chat surface renders the picture inline.
Add a download link. Because Download URL gives a real, shareable link, reuse the same ImageUrl in a markdown link (drop the leading !) to offer a click-to-download option:
![image]({{Inputs.Nano_Banana.Output.Images[-1].ImageUrl}})

[⬇️ Download image]({{Inputs.Nano_Banana.Output.Images[-1].ImageUrl}})
💡 Using Base64 output instead? Embed it as a data URI rather than a plain URL: 
![image](data:{{Inputs.Nano_Banana.Output.Images[-1].MimeType}};base64,{{Inputs.Nano_Banana.Output.Images[-1].ImageDataBase64}})

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Troubleshooting

The image won’t display / the link is empty
  • The Message Formatter references ImageUrl, but the step is set to Base64. Switch Output Format → Download URL, or embed the base64 data URI instead (see above).
The variable doesn’t resolve
  • Check the step title in the token. The default step Nano Banana is referenced as Inputs.Nano_Banana; spaces become underscores, and a numbered duplicate like Nano Banana 1 becomes Nano_Banana_1. The token must match the title exactly.
The download link stops working after a while
  • The signed URL expired. Increase URL Expiry, or set it to Perpetual for a non-expiring link.
Authentication errors
  • Either select a valid Google API Key credential on the step, or leave the credential blank to fall back to the Airia Key.