How big ChatGPT and Gemini images are
- ChatGPT has made images at 1,024 × 1,024 (square), 1,024 × 1,536 (portrait) or 1,536 × 1,024 (landscape). OpenAI's newer GPT Image 2, released in April 2026, can go up to about 8 megapixels through its API, but what the ChatGPT app gives you varies, so check the file.
- Gemini's standard image model (Nano Banana) makes images of about 1,024 pixels. Nano Banana Pro offers 1K, 2K and 4K, up to 4,096 × 4,096, with the bigger sizes on paid plans.
| Image | Pixels | Sharp (inches) | Fine on a wall (inches) |
|---|---|---|---|
| ChatGPT square | Pixels: 1,024 × 1,024 | Sharp (inches): 3.4 × 3.4 | Fine on a wall (inches): 6.8 × 6.8 |
| ChatGPT portrait or landscape | Pixels: 1,024 × 1,536 | Sharp (inches): 3.4 × 5.1 | Fine on a wall (inches): 6.8 × 10.2 |
| Gemini at 1K | Pixels: 1,024 × 1,024 | Sharp (inches): 3.4 × 3.4 | Fine on a wall (inches): 6.8 × 6.8 |
| Gemini Nano Banana Pro at 2K | Pixels: 2,048 × 2,048 | Sharp (inches): 6.8 × 6.8 | Fine on a wall (inches): 13.6 × 13.6 |
| Gemini Nano Banana Pro at 4K | Pixels: 4,096 × 4,096 | Sharp (inches): 13.6 × 13.6 | Fine on a wall (inches): 27.3 × 27.3 |
Checked October 2026. Both change often; on a phone, open the downloaded image and swipe up to see its size.
Why asking for "higher resolution" doesn't work
It's the obvious thing to try, and it backfires. A chatbot can't add pixels to the image it already made. Asked for a higher resolution or 300 DPI, it either generates a new image, where faces, text and small details change, or hands back the same pixels with a different DPI label, which prints exactly the same.
Ask the chatbot for what it can do well: the right content and the right shape. Then make it bigger with an upscaler, which keeps the picture you approved.
Getting one print-ready
- 1
Ask for the shape in the prompt
Say "portrait" or "landscape" and the print it is for. ChatGPT only offers a few shapes (square, 2:3, 3:2), so an 8×10 (4:5) or 11×14 still needs adjusting later. Gemini accepts more aspect ratios; ask for 4:5 or 3:4 directly.
- 2
Download it properly
Use the image's download button. A screenshot or a long-press copy can be smaller, and includes whatever else was on the screen.
- 3
Fix the shape without cropping
A 2:3 ChatGPT image going onto an 8×10 loses part of the top and bottom if cropped. Extending it adds matching background instead. If there is room to spare, crop it free.
- 4
Upscale to the print size
Upscale it to the exact pixels the print needs: 2,400 × 3,000 for a sharp 8×10, or 2,400 × 3,000 for a 16×20 on a wall. Check text and faces at full size before ordering the print.