Nano Banana 2.1 vs GPT Image 2.5: Same-Prompt Test in 5 Tasks

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Quick answer: in our five-task, same-prompt test, Nano Banana 2.1, the default model in Fuser's Gemini Image node, won the product shot, tied GPT Image 2.5 Flare on poster text and returned the larger images at its 2K default. GPT Image 2.5 Flare won the character test clearly and the photo and edit tests narrowly: it carried a face from a reference more faithfully, rendered readable shop signs and kept every detail of an edited product. Both run as nodes in Fuser, so one prompt can feed each and you keep whichever result fits. This was one run per model per task, so read it as a guide to tendencies, not a benchmark.

How we tested

We ran five prompts through each model on 6 October 2026: one generation each, no retries, no cherry-picking.

• Models: Nano Banana 2.1 (model ID gemini-nano-banana-2.1) and GPT Image 2.5 Flare (gpt-image-2.5-flare), the default model in each of Fuser's Gemini Image and GPT Image nodes. In Fuser both nodes call Google and OpenAI directly; for this test we generated the images with the same model versions.

• Settings: each node's defaults, except PNG output. Nano Banana 2.1 at 2K resolution; GPT Image 2.5 Flare at quality "auto". We matched the aspect ratio per task: 3:2 (1536 × 1024 for GPT Image) for the photo and product tests, 2:3 (1024 × 1536) for the poster and the character test, and "auto" for the edit, so both kept the square input. Nano Banana 2.1 returned 2528 × 1696, 1696 × 2528 and 2048 × 2048; GPT Image returned exactly the sizes requested and 1024 × 1024 for the edit.

• Inputs: the edit and character tests start from images made with a third model, FLUX.2 [pro], so neither model was editing its own output.

• Prompts: the same five prompts as our September test of Nano Banana 2, written with both vendors' published advice in mind: required words in quotation marks, the preserved details listed in edits, and "photorealistic" stated when that was the goal (OpenAI image prompting guide, Google DeepMind prompt guide).

We compared the results by eye at full resolution, including crops of hands, faces, labels and small type.

Test 1: photoreal scene

Prompt: "A photorealistic candid photograph of an elderly fisherman mending a bright orange net on a weathered wooden dock at dawn. Mist hangs over the harbour behind him, his calloused hands are in sharp focus, and the background falls off into soft blur. Natural light, 50mm lens look, muted colours."

• Nano Banana 2.1 made a wide, cool, misty scene: the whole fisherman seated on a crate, sharp knuckles and a netting needle threaded with twine, and no text anywhere in the frame. The boats and sheds behind him stay fairly sharp, and the light reads as overcast rather than dawn.

• GPT Image 2.5 Flare framed closer, with the hands and needle in crisp focus, the harbour dissolving into soft blur and warm lamps still lit along the water, which reads as early morning. Nothing branded appears.

Verdict: GPT Image 2.5 Flare, narrowly, for the blur and dawn cues the prompt asked for. Pick Nano Banana 2.1 when you want the whole scene and more pixels to crop from.

Test 2: text on a poster

Prompt: "A minimalist screen-printed concert poster on off-white paper. A large deep-blue wave shape fills the top half. Below it, the headline "NIGHT TIDE" in a bold condensed sans-serif, then "Live at Harbour Hall" in a lighter weight, then "Friday 14 November · Doors 8 PM", and at the bottom "harbourhall.com/nighttide" in small type. No other text."

• Nano Banana 2.1 spelled every line correctly, kept the exact middle dot and set a lighter second line under a condensed headline. It drew a hand-cut, linocut-style wave and presented the poster as a sheet lying on a pale surface.

• GPT Image 2.5 Flare also spelled every line correctly and returned flat, full-bleed artwork you could hand to a printer. It swapped the middle dot for a larger bullet.

Verdict: a tie on accuracy. Google lists "enhanced text rendering and infographic layout accuracy" among Nano Banana 2.1's updates (Gemini API), and both vendors say to put the exact wording in quotes (Google DeepMind, OpenAI). For more text-heavy tests, see best AI models for text in images.

Test 3: product shot with copy space

Prompt: "Studio product photograph of a matte sage-green ceramic pour-over coffee dripper sitting on a pale oak board. Soft window light from the left, a gentle shadow to the right, clean off-white background, with empty space on the right third of the frame for ad copy. Real photograph, no props."

• Nano Banana 2.1 followed the set literally: a separate pale oak board, light from the left, a clear soft shadow falling right and open space on the right. The dripper is clean and unbranded.

• GPT Image 2.5 Flare made the more detailed dripper, with ribs inside the cone, and left open space on the right. It placed it on an oak tabletop rather than a board, and the shadow to the right barely reads.

Verdict: Nano Banana 2.1, the closer match to the brief. For more product workflows, see best AI product photography tools.

Test 4: edit the setting, keep the product

Input: a studio packshot of an amber serum bottle labelled "LUMA 02". Prompt: "Place this exact bottle on a wet, moss-covered river stone outdoors in soft morning sunlight, with a blurred forest stream behind it. Change only the setting and lighting. Keep the bottle's shape, amber glass, black dropper cap and the label text "LUMA 02" exactly as they are."

• Nano Banana 2.1 kept the bottle's shape, amber glass and the "LUMA 02" label clean and unchanged, in a wider scene with a rushing stream that is only partly blurred. It also restyled the cap, adding vertical ribs to the smooth collar of the original.

• GPT Image 2.5 Flare kept the bottle, label and the smooth glossy cap as they were, framed the bottle larger and put it against a soft, sunlit, blurred stream. It added water droplets to the glass and cap.

Verdict: GPT Image 2.5 Flare, narrowly, because it changed nothing the prompt said to keep. The "change only X, keep Y" pattern is OpenAI's documented approach to edits (OpenAI); check small hardware details like caps and closures in any edit. Compare more editors in best AI image editing models.

Test 5: same person, new scene

Input: a head-and-shoulders portrait of a woman with curly copper-red hair, freckles and round tortoiseshell glasses. Prompt: "Show the woman from the reference image riding a bicycle down a rainy city street at night, lit by neon shop signs, wearing a yellow raincoat with the hood down. Keep the same face, curly copper-red hair, freckles and round tortoiseshell glasses. Full-body shot, photorealistic."

• Nano Banana 2.1 made a natural full-body shot in heavy rain, but loosened the curls into waves, faded the freckles and thinned the glasses. Its shop signs are illegible.

• GPT Image 2.5 Flare carried the face over clearly: tight copper curls, freckles, tortoiseshell glasses and even the mustard sweater from the reference under the raincoat. Its neon signs read "COFFEE", "BOOKS" and "BAR".

Verdict: GPT Image 2.5 Flare. For character work with several references, Google rates Nano Banana 2.1 for consistency across up to four characters (Gemini API), and its prompt guide recommends giving each character a distinct name (Google DeepMind). See consistent characters with AI for a multi-image workflow.

What each model offers beyond this test

• Nano Banana 2.1 (gemini-nano-banana-2.1): Google's update to Nano Banana 2, released on 6 October 2026, with 1K, 2K and 4K output, grounding with Google Web and Image Search, configurable thinking levels and a SynthID watermark on every image (Gemini API, image generation guide). Google charges per image, at half Nano Banana 2's rate. Nano Banana 2 itself shuts down on 29 October 2026 (release notes); the Nano Banana 2.1 guide covers the switch, and our Nano Banana 2.1 vs Nano Banana 2 vs Pro test compares the Google models head to head.

• GPT Image 2.5 Flare: OpenAI's guidance is "Sunburst for workflows where editing precision matters most, and Flare for fast, high-quality everyday image generation" (OpenAI). It supports masks, transparent backgrounds, quality from low to max, and custom sizes up to 3840 pixels on either edge (OpenAI). It is billed by image output tokens rather than a flat price per image (model page).

Settings in Fuser

The Gemini Image node defaults to Nano Banana 2.1 at 2K and "Auto" aspect ratio. It also offers Nano Banana 2, Nano Banana 2 Lite, Nano Banana Pro and Gemini 2.5 Flash Image, 1K to 4K output, up to 10 reference images, a system prompt field and a Search Grounding toggle.

The GPT Image node defaults to GPT Image 2.5 Flare with size and quality on "auto". It also offers GPT Image 2.5 Sunburst, GPT Image 2 and older versions; sizes up to 3840 × 2160; quality up to "max"; a mask input for local edits; and a transparent-background toggle for text-to-image.

To run this comparison on your own brief, put one prompt in a text node, wire it into both nodes and compare the results side by side on the canvas, as in the image at the top. Prompt guides for each model: Nano Banana and GPT Image.