Precise Local Editing (Red Box/Mask): Pixel-Level Precision Control

Feature Description

In image editing, we often need to modify only a specific part of the image rather than making global adjustments. Nano Banana provides a powerful precise local editing feature that uses "red boxes" or "masks" to accurately specify editing areas, enabling replacement, enlargement, or modification of local elements while ensuring the rest of the image remains completely unchanged. Whether you want to replace an object in a person's hand or enlarge a specific person in a group photo, this feature provides pixel-level precision control. It's a core advanced technique for achieving complex creativity and detailed retouching.

Operation Steps

Operation

  1. Prepare Materials: Prepare an image that needs editing.
  2. Create Editing Area: Use your phone's built-in image editor or tools like PowerPoint to draw a red box around the area you want to edit, or create a mask by painting with red.
  3. Upload Image: Upload the processed image to Nano Banana.
  4. Input Prompt: Enter clear instructions describing what operation you want to perform on the red box/mask area.
  5. Generate and Refine: Nano Banana will output the result. You can iterate and optimize as needed.

Prompt Example

Red Box Extraction and Enlargement

Chinese Prompt

将红色盒子里的男人分开,变成一张高清单人照片。

Prompt Box (Recommended prompt, English works best)

Separate the man in the red box and turn him into a high-resolution solo portrait.

Mask Area Content Replacement

Chinese Prompt

将蒙版区域替换成一个香奈儿包。

Prompt Box (Recommended prompt, English works best)

Replace the brushed area (red mask) with a Chanel bag, ensuring it integrates naturally with the scene's lighting and perspective.

Prompt Breakdown

  • Specify the Area: The prompt explicitly identifies the operation target as the man in the red box or the brushed area, directly guiding the AI to focus on the area you've marked.
  • Define the Task: The instruction clearly describes the operation to be performed, such as Separate... and turn him into... (separate and transform) or Replace... with... (replace), avoiding ambiguity.
  • Emphasize Natural Integration: When performing object replacement, you can add descriptions like ensuring it integrates naturally with the scene's lighting and perspective to achieve more realistic composite effects.

Output Image Example

"Before & After" Comparison

Nano Banana using red box feature to extract and enlarge a person from a group photo
Image description: Left side shows a group photo with one person circled by a red box. Right side shows a high-resolution solo portrait generated by Nano Banana with the background automatically filled in.

Nano Banana using mask feature to replace an item in the image with a Chanel bag
Image description: Left side shows a portrait photo with the carried bag covered by a red mask. Right side shows the effect generated by Nano Banana, where the mask area is naturally replaced with a Chanel bag.

Core Value / Management Perspective

Precise local editing is a key feature that elevates Nano Banana from "one-click generation" to "detailed creation." Its core value lies in empowering users with extremely high levels of control and creative freedom:

  • Solve AI "Uncontrollability" Pain Point: Traditional AI generation has randomness, making it difficult for users to control details. This feature returns creative control to users by allowing area-specific operations, turning AI into an obedient and precisely controllable tool.
  • Improve Complex Task Processing Efficiency: For detailed work such as e-commerce product image replacement or advertising poster element fine-tuning, there's no longer a need to rely on professional designers for complex Photoshop operations. Operations or marketing personnel can quickly complete modifications, significantly improving work efficiency.
  • Unlock Advanced Creative Possibilities: For example, e-commerce operations can mark a specific area of a product image and have AI "create from nothing" by adding brand elements or decorations, greatly expanding the creative space for marketing materials.

Related Usage Recommendations

  • Multi-Image Fusion and Collage (Coming Soon): When you need to fuse multiple subjects, you can first process each element separately with this feature, then collage them together for higher accuracy.
  • Element Add, Remove, and Replace: Local editing is the technical foundation for achieving precise addition, deletion, and replacement. Combining both yields even better results.
  • Product Images and Advertising Posters (Coming Soon): After generating advertising posters, you can use this feature to fine-tune and replace products, logos, or text in the poster.
  • AI Video Generation: You can first use the local editing feature to create "before" and "after" keyframes, then use video generation tools to create dynamic transformation video effects.