Seedream 5.0 Pro vs Nano Banana Pro: Same-Prompt Test and Price

Weighing GPT Image 2 too? Our Seedream 5.0 Pro vs GPT Image 2 test covers it, and Nano Banana 2.1 vs Pro covers Google's newer model.

The price row uses each vendor's own rate, BytePlus per image and Google per token, and both models run on OmniaKey: Seedream 5.0 Pro and Nano Banana Pro.

How we tested

• Models and IDs: Seedream 5.0 Pro (Dola-Seedream-5.0-pro) and Nano Banana Pro (gemini-3-pro-image). ByteDance's own BytePlus ID is dola-seedream-5-0-pro-260628, and Google's model card lists gemini-3-pro-image.
• October 31, 2026, through OmniaKey's media API.
• Sizes and settings: Seedream took size 2496x1664 for landscape work and 1664x2496 for the poster, with watermark false. Nano Banana Pro took aspect_ratio 3:2, or 2:3 for the poster, with image_size 2K, which returned 2528×1696 and 1696×2528.
• One run per test and two for the poster: 6 images per model, 12 in all, plus one source photo for the edit.
• The edit input came from a third model, GPT Image 2 (gpt-image-2, 1536×1024, quality medium, 33.6 s), so neither model edited its own picture. We sent it as a 1024×683 JPEG because one request is capped at 1 MiB, in input.images as a data URL for Seedream and in input.image with data and mime_type for Nano Banana Pro.
• Time is submit to finished image on the task API, including queue and network.
• We judged at full size: each requested word letter by letter, anything added, the listed edit details, and the diagram's order, colors and symbols.
• OmniaKey sells API access to both models, so we ran the tests through it. Every price is the vendor's own rate, not ours.
• Sources, all checked October 31, 2026: ByteDance's Seedream 5.0 Pro post, BytePlus ModelArk pricing, Volcengine's Seedream 5.0 Pro docs and image API page, and Google's Gemini 3 Pro Image model card, Model Garden pricing, Nano Banana Pro announcement and model page.

This is one or two runs per test, so treat the images as examples rather than a benchmark.

Five tests, same prompts

Test 1: Documentary photo (3:2)

This test checks a believable photo: skin texture, sharp gears, blurred clocks, no text.

Prompt:

A candid documentary photograph of an elderly watchmaker repairing a mechanical watch at a cluttered wooden bench beside a north-facing window. He holds fine steel tweezers in his right hand and steadies the open watch with his left, with a loupe over one eye. Deep wrinkles, age spots and visible skin texture on his hands and face. The tiny gears are in sharp focus, and the shelves of old clocks behind him fall into soft blur. Natural window light, 35mm film look, no text, no logos.

• Seedream 5.0 Pro (57.5 s): An older man in a white work coat with a loupe over one eye and tweezers in one hand, while the other steadies the open watch on a small holder. Cluttered bench, blurred shelf of clocks behind, window light, age spots and skin texture on his scalp, face and hands, no border and no text.
• Nano Banana Pro (37.4 s): A profile view with the loupe clipped onto his glasses, the open watch in one hand and tweezers in the other. A paper mat with oil jars, a spare loupe and small parts, deep forehead wrinkles, and a black film-frame border that the prompt never asked for.

Verdict: Seedream, narrowly. Both look like real photos with believable hands, and Nano Banana Pro's film border has to be cropped before use, though it followed “steadies the open watch with his left” more literally.

Test 2: Bilingual poster (2:3)

This test checks every printed line, including the en dash and the middle dots.

Prompt:

A vertical poster for a night market. Large headline in Chinese: "河畔夜市". Under it in English: "Riverside Night Market". Date line: "Friday 20 November, 18:00–23:00". Footer line: "40 food stalls · Free entry · 免费入场". Deep blue background, warm paper lanterns illustrated across the top, clean layout with generous margins. Spell every word exactly as written and add no other text.

• Seedream 5.0 Pro (71.9 s and 62.2 s): Run 1 set the Chinese headline in gold brush calligraphy, serif English lines, a footer between two round line icons and plum-blossom lanterns across the top. Run 2 kept the brush headline, set the date line in italic and added a riverside scene with stalls, people and a moon that nobody asked for, with all four lines exact in both runs.
• Nano Banana Pro (32.1 s and 32.5 s): Run 1 used a bevelled bold sans-serif headline, plain sans-serif English lines and round lanterns on strings across the top. Run 2 set the headline in thin sans-serif with floating sky lanterns and a condensed date line, plainer and closer to a template, with all four lines exact in both runs.

Verdict: Tie. All four posters spelled every line exactly, including the en dash in 18:00–23:00 and the middle dots. Seedream's brush lettering looks hand-made and Nano Banana Pro's posters are plainer, so pick by style.

Test 3: Product shot with copy space (3:2)

This test checks the three label lines, the empty left third and any unrequested words.

Prompt:

Studio product photograph of a matte sage-green aluminum can of sparkling water with a printed label. The label reads "SOLA" in large letters, "Yuzu & Sea Salt" under it, and "330 ml" at the bottom. Cold condensation droplets on the can, standing on a wet slate slab. The can sits on the right third of the frame and the left third stays empty for ad copy. Soft side light, plain dark-grey background, no other text, no other logos.

• Seedream 5.0 Pro (63.0 s): The three lines printed straight onto the matte green can in white, exactly the requested words and nothing else, with the last two letters of SOLA a little paler. Droplets on wet slate, a dark-grey background, and the can right of center with the left side empty.
• Nano Banana Pro (33.6 s): A cream paper label wrapped around the can with SOLA in black, “Yuzu & Sea Salt” and “330 ml”, plus an extra line, “Sparkling water”, at the top of the label. The can sits right of center and smaller in the frame, and the left side is empty.

Verdict: Seedream. Only the requested words came back, and Nano Banana Pro's extra line would need a retouch before an ad runs.

Test 4: Photo edit to dusk snow (3:2)

This test checks whether the scene turns to heavy snowfall at dusk while the face, raincoat, cup, blue door and sign stay the same.

The source photo came from GPT Image 2 with this prompt:

Prompt:

A realistic street photograph of a young woman in a mustard-yellow raincoat holding a white paper coffee cup, standing outside a small bakery on a sunny morning. The shop sign above the window clearly reads "LUNA BAKERY" in dark green letters. She looks slightly to the left of the camera and smiles. Dry pavement, clear daylight, a blue door to the right of the window. No other text.

The edit prompt:

Change this scene from a sunny morning to heavy snowfall at dusk, with snow settled on the pavement and the sign ledge and warm lights glowing inside the bakery window. Keep the woman's face, her mustard-yellow raincoat, the white paper cup, the blue door and the sign reading "LUNA BAKERY" exactly the same.

• Seedream 5.0 Pro (108.2 s): The slowest image of the test, with dusk light, a wall lamp on, a warm bakery window and snow settled on the pavement, the ledge and the shrub, which became a snow-covered conifer. Sign, coat, cup and door stayed, her face stayed close to the source, and her dark-brown hair turned black with snowflakes in it.
• Nano Banana Pro (33.0 s): Heavy falling snow, snow along the sign, a warm window, and the face and dark-brown hair closest to the source, with the sign, coat, cup and door kept. The light stayed daytime, with sun on her face and blue sky with clouds at the top left, so the scene never reached dusk.

Verdict: Split. Seedream did the scene change but changed her hair color. Nano Banana Pro kept the person but stayed in daylight.

Test 5: Technical diagram (3:2)

This test checks the numbered order, the pipe colors, the outside labels and the symbols.

Prompt:

A clean technical infographic titled "How a heat pump works". Draw one closed loop with exactly four labelled parts in this clockwise order, starting at the top left: 1 Evaporator, 2 Compressor, 3 Condenser, 4 Expansion valve. Arrows show the flow direction around the loop. The pipe is blue from part 4 through part 1 to part 2, and red from part 2 through part 3 to part 4. Outside the loop, write "Outside air" next to part 1 and "Warm room" next to part 3. Flat vector style, white background, dark text. Spell every label exactly as written and add no other text.

• Seedream 5.0 Pro (56.8 s): The title spelled right, the four parts exactly where asked from 1 Evaporator at the top left clockwise to 4 Expansion valve at the bottom left, blue and red in the right places and clockwise arrows. Every label is spelled right with no extra text, but the expansion valve is an unreadable black shape, the compressor is a black box with a red dot and small decorative arrows point in mixed directions.
• Nano Banana Pro (32.4 s): Numbered circles in clockwise order with part 1 at the middle of the left side rather than the top left, blue and red in the right places, coils for the evaporator and condenser and a textbook valve symbol. “Outside air” and “Warm room”, each with an icon, sit outside the loop, every label is spelled right and the compressor is drawn as a pipe fitting.

Verdict: Nano Banana Pro, narrowly. Both carry the same correct content, and its symbols read like a textbook while Seedream's valve is unreadable.

Results by test

Price and speed

Seedream bills per image and Nano Banana Pro per token, and these are the vendors' own rates, checked October 31, 2026.

BytePlus's ModelArk pricing page lists $0.09 per Seedream 5.0 Pro image above 2.61 million pixels and $0.045 up to that line, and our 2496×1664 images are 4,153,344 pixels. Failed images, for example on content moderation, are not billed, and the edit cost $0.09 too because the first input image is free while each extra one is $0.003.

Google's Model Garden pricing page lists $120 per million image output tokens, which is $0.134 for the 1,120 tokens in every 1K or 2K image. Input is $2.00 per million tokens and text output, thinking included, is $12.00, and with 101 to 141 prompt tokens and 172 to 282 thinking tokens per run, each image came to $0.1367 to $0.1381. Thinking adds about $0.002 to $0.003.

At 2K as tested, one Nano Banana Pro image costs about 1.5 times a Seedream image, $0.137 against $0.09. At Seedream's 1.5K tier the gap is about 3 times, $0.137 against $0.045, because Google charges the same $0.134 for 1K and 2K.

New images took a median 62.2 s on Seedream against 32.5 s on Nano Banana Pro, so Nano Banana Pro was about 1.9 times faster. The edit took 108.2 s against 33.0 s.

Do ByteDance's and Google's claims hold up?

ByteDance says Seedream 5.0 Pro "accurately transforms data, concepts, and dense text into professional layouts" and plans infographic layouts itself. In our diagram every label was right and every part sat where the prompt put it, while the expansion valve came out as an unreadable black shape.

ByteDance also says "there is still room to improve in finer-grained text rendering and pixel-level editing consistency". All four text images came back with every requested word right, and the edit changed her dark-brown hair to black, which is the kind of consistency slip that sentence describes.

Google says Nano Banana Pro "is the best model for creating images with correctly rendered and legible text directly in the image". It spelled all four poster lines and every diagram label exactly, and on the can label it added the words "Sparkling water".

Google also says the model "can still struggle with small faces, accurate spelling, and fine details", and that in infographics and diagrams "it may misinterpret information or produce factually incorrect results". Here the spelling was exact, the face and hair stayed closest to the source and the diagram symbols read clearly, though part 1 landed mid-left instead of top left.

ByteDance's own Dreamina comparison page, dated February 3, 2026, says "Nano Banana Pro renders quickly, ideal for rapid iteration and feedback. Seedream 5.0 offers moderate speed", and it compares Seedream 5.0 rather than 5.0 Pro. Our medians, 62.2 s against 32.5 s, and 108.2 s against 33.0 s on the edit, point the same way.

ByteDance announced Seedream 5.0 Pro on July 8, 2026. Google announced Nano Banana Pro on November 20, 2025, and its model card lists gemini-3-pro-image as generally available on May 28, 2026.

Watermarks and labels

Seedream's watermark parameter adds an “AI生成” (“AI generated”) mark in the bottom-right corner and is on by default, so we sent "watermark": false and our six Seedream images came back without it. Google says every Nano Banana Pro image carries an invisible SynthID watermark, and its announcement says the visible Gemini sparkle stays only on images from free and Google AI Pro tier users. None of our 12 images carried a visible mark.

Pros and cons

Seedream 5.0 Pro

• Pros: exactly the requested words on all four text images; the lower 2K price, $0.09, or $0.045 at 1.5K; turned the edit to dusk.
• Cons: 62.2 s median for new images and 108.2 s for the edit; darkened her hair; drew an unreadable expansion valve.

Nano Banana Pro

• Pros: 32.5 s median and 33.0 s on the edit; kept her face and hair color; clear textbook symbols.
• Cons: added “Sparkling water” to the can label; drew a film border nobody asked for; missed dusk in the edit; about 1.5 times the price.

Which one for which job

Run the same test through one API

This request makes the Test 3 can with Seedream at 2496×1664, with the AI-generated mark turned off:

curl https://api.omniakey.com/v1/media/tasks \
  -H "Authorization: Bearer $OMNIAKEY_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: sola-can-001" \
  -d '{
    "model": "Dola-Seedream-5.0-pro",
    "type": "image",
    "operation": "generate",
    "input": {"prompt": "Studio product photograph of a matte sage-green aluminum can of sparkling water with a printed label. The label reads \"SOLA\" in large letters, \"Yuzu & Sea Salt\" under it, and \"330 ml\" at the bottom. Cold condensation droplets on the can, standing on a wet slate slab. The can sits on the right third of the frame and the left third stays empty for ad copy. Soft side light, plain dark-grey background, no other text, no other logos."},
    "parameters": {"size": "2496x1664", "watermark": false}
  }'

1. The reply is 202 with a task id.
2. Every few seconds, fetch https://api.omniakey.com/v1/media/tasks/{id} until status is succeeded.
3. Download the image from assets[0].url.

For Nano Banana Pro, set model to gemini-3-pro-image and parameters to aspect_ratio 3:2 with image_size 2K. To edit, set operation to edit and send the photo as in the test: a data URL in input.images on Seedream, data plus mime_type in input.image on Nano Banana Pro. Start on the Seedream 5.0 Pro and Nano Banana Pro model pages, and read the image API docs for every parameter.

Common questions

Which is better, Seedream 5.0 Pro or Nano Banana Pro?

Neither wins outright. Seedream printed only the words we asked for at $0.09 per 2K image, while Nano Banana Pro was about twice as fast at 33 s, kept the woman's hair in the edit and drew the clearer diagram at about $0.137.

What does each model cost per image?

BytePlus charges $0.09 per 2K Seedream 5.0 Pro image above 2.61 million pixels, and $0.045 up to that limit, so 100 images cost $9.00. At Google's token rates one 2K Nano Banana Pro image is about $0.137, or $13.73 for 100.

Which one is faster?

Nano Banana Pro. New images took a median 32.5 s against 62.2 s on Seedream, and the same edit took 33.0 s against 108.2 s.

Do the images have watermarks?

No visible mark appeared on our 12 images, but Seedream's is on by default. Seedream adds an “AI生成” mark only while watermark is true, and we set it false. Google puts an invisible SynthID watermark in every Nano Banana Pro image and a visible sparkle only for free and Google AI Pro tier users.

Sources checked

• ByteDance: Introducing Seedream 5.0 Pro
• BytePlus: ModelArk pricing
• Volcengine: Seedream 5.0 Pro docs
• Volcengine: image generation API
• Google Cloud: Gemini 3 Pro Image model card
• Google Cloud: Model Garden pricing
• Google: Nano Banana Pro announcement
• Google DeepMind: Nano Banana Pro
• Dreamina: Seedream 5.0 vs Nano Banana Pro

Update log

• 2026-10-31: First version, with our same-prompt tests run on October 31, 2026.