The Complete Nano Banana Guide: Edit Images with Text in 5 Minutes Flat

Updated 14 Aug 2025

“I have a portrait shot and I only want to swap the background—without re-lighting the scene or asking the model to freeze in the exact same pose. Can one tool do that?”
Yes, and its name is Nano Banana.

Table of Contents

  1. What Exactly Is Nano Banana?
  2. How Does It Work Under the Hood?
  3. Everyday Use-Cases You Can Start Today
  4. Two Fast Ways to Run Your First Edit

    • Route A: Google Colab (zero install)
    • Route B: Local Machine (full control)
  5. Three Copy-and-Paste Prompt Recipes
  6. Straight Answers to the Most-Asked Questions
  7. How to Reproduce the Official Benchmarks
  8. Final Thoughts and Next Steps

1. What Exactly Is Nano Banana?

Nano Banana is a text-to-image editing model.
You feed it a sentence and an image, it returns the same image—but with only the parts you asked to change updated. Lighting, composition, style, and character identity stay intact.

Core Concept Plain-English Meaning Where You’ll See It
Text-to-image editing Write words → get picture edits Product photography, social posts
Local control Paint a mask → edit only inside Portrait retouching, ad creatives
Shared semantic space Words and pixels speak the same language Keeps global lighting unchanged

2. How Does It Work Under the Hood?

Think of Nano Banana as a bilingual translator.

  • Language 1: your prompt.
  • Language 2: the pixels in your image.

Step-by-step

  1. Encode both prompt and image into the same numeric “space.”
  2. Mark the region you want changed (with a mask or let the model infer).
  3. Iterate: the generator repeatedly tweaks only the masked pixels while checking, “Does this still match the prompt and the untouched surroundings?”
  4. Stop when the answer is “yes.” The untouched pixels remain pixel-perfect.

The whole loop finishes in 10–30 seconds on typical consumer GPUs.

3. Everyday Use-Cases You Can Start Today

Scenario One-Sentence Goal Prompt Example
Portrait retouch Keep the face, change the outfit “convert outfit to modern tactical style, keep face identity and hair”
Product shot Product stays, background goes “replace background with clean white studio, soft shadows”
Add an accessory Place a realistic object in hand “add a katana in right hand, realistic reflection and shadow”
Color style tweak Shift mood without redrawing “warm golden hour lighting, same composition”

4. Two Fast Ways to Run Your First Edit

Route A: Google Colab (Zero Install)

Best for:

  • No GPU on your laptop.
  • You want results in the next 5 minutes.
  • You’re okay uploading images to a temporary cloud VM.

Steps

  1. Open the official or community Colab notebook (link coming soon).
  2. Upload reference.jpg using the file-panel button.
  3. (Optional) Upload mask.png—white pixels = editable area.
  4. Paste the prompt and parameters from the recipe section below.
  5. Run all cells. Wait 10–30 seconds. Download the result.

Starter Prompt & Settings

replace background with neon cyberpunk city, preserve subject lighting and pose
seed=42 steps=30 guidance=4.0 strength=0.6

Route B: Local Machine (Full Control)

Best for:

  • You own an NVIDIA GPU.
  • You need batch processing or privacy.
  • You like command-line tools.

Steps

  1. Install Python 3.10+ and PyTorch with CUDA support (exact commands will be published soon).
  2. Download the model weights (link TBA).
  3. Open a terminal and run:
python edit.py \
  --input reference.jpg \
  --prompt "replace background with neon city" \
  --seed 42 --steps 30 --guidance 4.0 --strength 0.6
  1. Check the outputs/ folder for your new image.

5. Three Copy-and-Paste Prompt Recipes

Name Prompt Parameters Tips
Background Swap replace background with neon cyberpunk city, preserve subject lighting and pose seed=42 steps=30 guidance=4.0 strength=0.6 Lower strength (0.5–0.6) keeps the subject untouched.
Outfit Change convert outfit to modern tactical style, keep face identity and hair seed=42 steps=30 guidance=4.0 strength=0.55 Use the same seed across images to maintain character consistency.
Prop Insertion add a katana in right hand, realistic reflection and shadow seed=64 steps=32 guidance=4.5 strength=0.5 Draw a loose mask around the hand if you want the blade to blend naturally.

6. Straight Answers to the Most-Asked Questions

Q1: How is Nano Banana different from classic inpainting?
Classic tools fill holes using surrounding pixels; Nano Banana understands your sentence, so it can add or remove semantic objects, not just textures.

Q2: Can I use it commercially?
Check the license or Terms of Service of the exact release you run. When in doubt, start with non-commercial tests and read the provider’s terms.

Q3: Is there an API?
No stable public endpoints yet. The team will announce links as soon as they’re ready.

Q4: Do I have to draw a mask?
No. If you skip the mask, the model considers the entire image editable. A white-on-black PNG mask lets you restrict changes to specific regions.

Q5: How do I keep the same face across multiple images?
Use identical prompts, the same seed, and the same identity token (when available). See the Portrait Editing benchmark for side-by-side examples.

Q6: Why does my edit take 30 seconds while the docs say 10?
Higher resolution, older GPUs, or busy Colab VMs all add time. Lowering resolution or steps speeds things up.

Q7: How do I reproduce the official benchmark results?
Every benchmark page lists:

  • the original image
  • the exact prompt
  • seed, steps, guidance, strength

Match those values after finishing the Quickstart to obtain pixel-level identical outputs.

7. How to Reproduce the Official Benchmarks

  1. Download the reference image and optional mask from the benchmark page.
  2. Use the exact parameter string provided.
  3. Ensure you are running the same model weight version (version number is shown on the benchmark page).

If your result looks different, double-check the seed—one digit off changes everything.

8. Final Thoughts and Next Steps

  • You now know what Nano Banana is, why it keeps global lighting intact, and how to start editing in under five minutes.
  • Pick either Colab (fastest) or local (private) and run the starter recipe today.
  • Once you’re comfortable, batch-edit product shots or create character-consistent storyboards using the same seed.

Bookmark the official site; new installers and API news will appear there first.

Happy editing!