Aspect Ratio Workdaround

Question: 
Why does Google Gemini Nano Banana not follow the aspect ratio in the prompt? 

AI Overview

How to Control Image Aspect Ratio in Nano Banana : r/GeminiAI

Google's "Nano Banana" is not following aspect ratios in prompts because it's a known bug in the Gemini chat interface that defaults images to 1:1, prioritizing conversational editing over parameter commands. The most reliable workaround is to upload a separate blank or transparent image in the desired aspect ratio and prompt Gemini to "Add into and fill the attached image". Another option is to use Google's ImageFX tool, which provides a dedicated dropdown menu for selecting aspect ratios.  

Why the Issue Occurs 

• Technical Glitch: The Gemini chat interface's implementation of the "Nano Banana" image generation model has a bug that prevents it from correctly interpreting text-based aspect ratio commands.
  
  
• Prioritization of Conversation: The system's gemini-2.5-flash-image-preview model update in the chat UI prioritizes conversational editing over user control of parameters like aspect ratio.
  
  
• Backend Translation Failure: Gemini struggles to translate your natural language request for a specific aspect ratio into a structured technical command that the image generation model can execute.

Workarounds

• Use a Blank Reference Image (Recommended):

1. Create or download a blank or transparent image in your desired aspect ratio (e.g., 16:9 for landscape). 
2. In a new Gemini chat, upload the image you want to edit. 
3. Upload the blank reference image in the desired aspect ratio as the second (or last) image. Your prompt should instruct Gemini to "Add into and fill the attached image" (referring to the blank one), according to this Facebook post and this Reddit thread. 

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Use Google ImageFX:

ImageFX is Google's free image generation tool that offers a dedicated menu to select aspect ratios like Landscape or Portrait before generating an image.