I ran the same pencil sketch of a bear from my nephew through Nano Banana Pro and ChatGPT to see which one produces the most accurate and visually consistent upgrades.
Both tools can elevate a basic drawing into something awesome, but they behave differently. This breakdown shows what each model gets right, where each one drifts away like your ex, and how to choose the best option for your project.
Let’s party.
What I Tested in ChatGPT and Nano Banana Pro
To get a fair comparison, I used the same sketch and the same prompts for both models. Here is the sketch:
Each test introduced a different difficulty so we could see how well they maintain structure, follow instructions, and apply style changes.
The scenarios included:
• Clean cell-shaded anime conversion
• Graffiti on a Michigan train
• Heavy special effects without destroying the sketch
• A suburban wall scene with a person reacting
• A full enhancement pass that preserves composition
The ChatGPT & NBP Prompts + Direct Comparisons
Below is how each tool performed, along with the specific prompt for you to customize and test.
Because I was using my young nephew’s drawing, I wanted to include a few examples that any kid would find interesting: their drawing on a train, an anime transformation, and what it would look like if it were drawn on a wall. I also find those types of examples cool. They are cool, okay?
1. Anime Upgrade
Goal: Clean anime illustration with crisp lines, preserved proportions, and smooth cel shading.
Copy/Paste into ChatGPT
Upgrade the original drawing into a clean, high-quality anime illustration. Preserve the exact poses, proportions, and linework of the original sketch. Apply smooth, cel-shaded colors with defined highlights and shadows. Ensure the lines are crisp and the colors are vibrant, resulting in a polished anime-style keyframe animation cel that is a direct improvement on the initial drawing.
ChatGPT produced a polished anime look with strong shading. Nano Banana Pro kept the original linework more accurately. If you want high fidelity to your sketch, Nano Banana Pro held the advantage here.
Winner: Nano Banana Pro (1-0)
2. Graffiti on a Train
Goal: Turn the sketch into graffiti on a Michigan train with the “Harrison” tag and recognizable scenery.
Copy/Paste into ChatGPT
Take the drawing and turn it into graffiti on the side of a train in Michigan. Make it look as close to the original as possible, but in color, with some additional detail. Underneath the drawing, include the graffiti tag “Harrison”. The photo angle should show the train, as well as some Michigan scenery, trees, and plants.
ChatGPT followed the prompt closely and kept the composition intact. Nano Banana Pro delivered a more photorealistic image but drifted from the original structure.
This one was a tie. ChatGPT obeyed the brief. Nano Banana Pro served realism.
Winner: Tie (2-1)
3. Crazy Effects
Goal: Add fire, smoke, electricity, liquid, sparks, and other heavy effects while keeping the outline stable.
Copy/Paste into ChatGPT
Take the drawing and add all kinds of special effects like fire, smoke, electricity, sparks, liquid, etc. It should be partly psychedelic and partly paranormal. It should be awesome, insane, and awe-inspiring to everyone who sees it. It should be a marvel of eye candy. Go crazy. But keep the structure, outline, and original drawing intact as much as possible.
ChatGPT went creative with the effects. More stylized. More interpretive. Nano Banana Pro took the request like a lawyer reading a contract and followed it completely literally. It even preserved the original autograph frighteningly well, which was a common theme in the test.
Winner: ChatGPT (2-2)
4. Off the Wall
Goal: Make the drawing appear on a gray suburban wall with a black marker, plus an upset person reacting to it.
Copy/Paste into ChatGPT
Now make it look like the drawing was written on a gray wall with a black marker in a suburban house. Keep the drawing as close to the original as possible. Include someone who’s really upset that someone wrote all over their wall.
ChatGPT nailed the scene—suburban mood. Believable, annoyed human. Sketch intact. Nano Banana Pro delivered a hyperreal wall and a detailed bear, but the human character often looked strange. Distracting strange.
Winner: ChatGPT (2-3)
5. Overall Image Booster/Enhancer
Goal: Enhance the sketch into a refined piece while keeping the layout, proportions, and linework identical.
Copy/Paste into ChatGPT
Enhance the original pencil sketch while meticulously preserving its original composition, linework, and overall form. The goal is a refined and polished version, not a complete re-imagining. Add subtle details and textures that feel like a natural extension of the artist’s initial intent. Introduce sophisticated lighting and soft, realistic colorization to give the subject depth and presence. Maintain the charm and simplicity of the original drawing, elevating it to a finished, professional-looking piece.
Both tools improved it. Nano Banana Pro stood out again. The line fidelity was almost perfect. The model kept the structure one-to-one while adding depth, lighting, and polish.
Winner: Nano Banana Pro (3-3)
When to Use Nano Banana Pro vs. ChatGPT
For this highly specific use case involving drawings, let’s break down the results.
Nano Banana Pro works best when:
• You want faithful line and structure preservation
• You prefer photorealistic or hyper-detailed results
• You need effects added without losing the sketch
• Accuracy matters more than artistic reinterpretation
ChatGPT works best when:
• You want a creative or stylized upgrade
• You want flexibility and conceptual reinterpretation
• You prefer clean, prompt-driven execution
Both perform well, but they serve different creative needs for drawings.
Quick Tips for Better Output
• Tell the model exactly what must stay the same, such as the pose or linework.
• Use clear stylistic labels like cel-shaded anime or photorealistic graffiti.
• Mention structural preservation when accuracy is critical.
• Iterate often. Small wording changes make a big difference.
• Combine both tools if needed. One may provide better structure, while the other provides better texture or atmosphere.
• Get creative. Dump your output from either tool into Adobe Photoshop, Canva, Dzine, or any other design app to upgrade or edit it.
Prefer watching? Tune in to the YouTube version below, and be sure to subscribe to us on YouTube.
Wrapping It Up
So, technically, the result of this test was a tie.
Nano Banana Pro vs. ChatGPT comes down to your priorities. For this specific use case, if you want precision and faithful enhancement, choose Nano Banana Pro. If you want stylistic creativity and interpretation, choose ChatGPT. However, both are unbelievably powerful.
Test the prompts above with your own art. It doesn’t even have to be a drawing. It can be anything. Get creative. Then share how things went in the comments below.
Until next time, remember to run the prompts and prompt the planet.
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