Free tool · Runs in your browser · Nothing uploaded
Nano Banana Aspect Ratio Canvas Generator
Free-tier Gemini often ignores “16:9” in prompts and returns square images anyway. The reliable workaround: give Nano Banana a blank canvas at the exact ratio you want and ask it to fill the whole thing. Pick a ratio below, download the canvas, upload it to Gemini with the companion prompt.
1920 × 1080 px
Use the uploaded image as the canvas. Fill the entire canvas edge to edge with: [describe your scene]. Keep the exact dimensions of the uploaded image. Do not add borders, bars, frames, or padding — replace the blank canvas completely.
How to use it (three steps)
- Pick your ratio and size above, then download the canvas PNG.
- In Gemini, upload the canvas as an image and paste the companion prompt, replacing the bracketed part with your scene.
- Generate. Because Nano Banana edits preserve the uploaded image’s dimensions, the result comes back at your ratio. Iterate on the scene with follow-up messages — the ratio stays locked.
Why prompting “make it 16:9” fails
On the free Gemini tier, ratio words in a text prompt are treated as soft styling hints, and users report square output no matter how the request is phrased — see the recurring threads on Google’s support forum (“nano banana can’t create 16:9”, “stuck at 1:1 despite 16:9 prompt”). Editing an uploaded image is different: the model works within the pixels it was given, so the canvas’s dimensions carry through to the output. That is the entire trick — no settings, no third-party apps, just a correctly sized blank image.
Once the ratio is locked, prompt quality still decides the picture. Build the scene description with our Nano Banana prompt generator, or start from tested realistic-photo prompts. If the output comes back soft or plastic-looking, run it through the image fix snippet picker.
FAQ
Why does Nano Banana ignore my aspect ratio request?
On the free Gemini tier, Nano Banana often outputs square-ish images even when the prompt clearly asks for 16:9 or 9:16 — users have reported this repeatedly on Google’s own support forum. The model treats ratio words as loose style hints rather than hard constraints. Uploading a canvas image of the exact ratio you want is the reliable community workaround, because image edits preserve the dimensions of the uploaded image.
How does the blank canvas trick work?
You give Gemini an image to edit instead of asking it to create one from scratch. Download a blank canvas at your target ratio from this tool, upload it to Gemini, and ask the model to fill the entire canvas with your scene. Because Nano Banana keeps the input image’s dimensions during edits, the output comes back at your ratio.
Should the canvas be transparent, white, or black?
Transparent works for most cases and makes the “replace the canvas completely” instruction unambiguous. If your Gemini version rasterizes transparency oddly, try the white canvas; use black when you want the model to build a dark scene and preserve deep shadows.
Does this still matter on Nano Banana Pro?
Less so — newer and paid tiers expose more direct aspect-ratio control. This tool exists for the free Gemini tier and for any version that ignores ratio wording in prompts. If your tier respects “16:9” natively, you don’t need a canvas.
Is this free? Do you see my images?
Free, no sign-up, and nothing is uploaded anywhere — the canvas is generated entirely in your browser with the HTML canvas API and downloaded straight to your device.